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10 Base-T Basic Ethernet at 10 Mbit/sec
100 Base-T Ethernet running at 100 Mbit/sec
1000 Base-T Ethernet running at 1,000 Mbit/sec
128QAM QAM with 7 bits per symbol.
16QAM QAM with 4 bits per symbol.
1G First Generation. Refers to analog cellular systems
1x A cdma2000 notation that indicates that one carrier is being used. Compare with 3x
1XRTT cdma2000 operating mode at basic chip rate (1.2288 Mcps). The theoretical top speed is 153 kbps
2G Second Generation. Refers to digital cellular and PCS wireless systems oriented to voice and low speed data services
2R Receive, Reshape (an optical signal). See 3R
32QAM QAM with 5 bits per symbol.
3G Third Generation. Refers to the next generation of wireless systems - digital with high speed data. Being standardized by 3GPP and 3GPP2
3GiA 3G Internet Appliance
3GPP 3rd Generation Partnership Project for W-CDMA (GSM)
3GPP2 3rd Generation Partnership Project for cdma2000
3GSP 3G Service Provider
3R Reshaping, Retiming, Reamplifying (an optical signal). See 2R
3WC Three Way Call
3x A cdma2000 notation that indicates that three carriers are being used. Compare with 1x. Not widely implemented. Although this allows higher maximum speeds, the average speed per user will not change significantly
3XRTT cdma2000 operating mode at 3 times the basic chip rate of 1.2288 Mcps
64QAM QAM with 6 bits per symbol.
802.11 An IEEE committee that standardizes a wireless Ethernet replacement technology in the ISM band. 802.11b is most commonly implemented and runs at approximately 10 Mbps in the 2.4GHz band. 802.11a runs at 54 Mbps in the 5 GHz band. 802.11g provides 24 Mbps in the same band as 802.11b.
802.11a A WiFi WLAN variant that is higher speed (54 Mbps) than 802.11b. Because it also operates in a different frequency band it has proven less popular than 802.11g which offers higher speed in the same band as 802.11b thus providing a simpler migration strategy. The range of this protocol is also lower and the LOS requirements more stringent. See ADRC
802.11b IEEE Wireless LAN system providing throughput of about 11 Mbps but see ADRC
802.11c An IEEE standard for network interoperability between WLAN protocols
802.11d An IEEE standard for operation of their WLAN protocols outside the normal frequency bands (e.g. due to the unavailability of those bands in some countries)
802.11e An IEEE standard for QoS in their WLAN protocols 802.11a, 802.11b, 802.11g and 802.11n
802.11f An IEEE standard for interconnection between wireless APs
802.11g A second generation version of WiFi providing 54 Mbps raw throughput (typically a user data rate of about half that) in the same 2.4 GHz frequency band as 802.11b. This gave it an advantage over 802.11a which had similar performance but operated in a different frequency band.
802.11h An IEEE standard for spectrum and transmit power management for their WLAN protocols
802.11i Enhanced security for IEEE WLAN protocols
802.11j An adaptation of 802.11 WLAN protocols to the Japanese 4.9–5 GHz frequency band
802.11k A proposed IEEE standard for RRM
802.11m A group for editorial maintenance of IEEE 802.11 WLAN standards
802.11n A future IEEE WLAN protocol that promises raw data rates of 540 Mbps in either the 2.4 GHz or 5 GHz band and thus will likely eventually replace 802.11a, 802.11b and 802.11g. The protocol is scheduled for completion in 2009. See EWC
802.11p A proposed IEEE standard for ITS. Also known as WAVE
802.11r A proposed IEEE standard for handoff between APs
802.11s A proposed IEEE standard for mesh networking
802.11t A proposed test specification for IEEE WLAN standards
802.11u A proposed standard for authorization of users on IEEE WLANs
802.11v A proposed wireless network management standard for IEEE WLAN protocols
802.11w A proposed standard for the protection of system management information in IEEE WLAN protocols
802.11y A proposed standard for operation of IEEE WLAN protocols in the 3.65-3.7 GHz frequency band
802.15 See Bluetooth
802.16 IEEE WiMax radio interface.
802.3 IEEE standard for Ethernet
8PSK PSK with 8 states, allowing the coding of 8 bit combinations. It is used in EDGE.
8QAM QAM with 3 bits per symbol.
911 The ES service code in many parts of the United States, Canada and a few other countries.


A(2) An IP host address
A-bis Interface between BTS and BSC
A-GPS Assisted GPS. Network provides information to mobile device to acquire satellite signals and may assist with processing of received data
A-interface Interface between the MSC and BS
A-Key The primary CAVE authentication key, used to generate SSD
A/D Analog/Digital. Usually used in the context of conversion from analog to digital (or vice-versa)
A3 GSM authentication algorithm
A5 GSM data encryption algorithm
A5/3 An encryption algorithm for GSM and EDGE
A8 GSM voice encryption algorithm. Used to generate Kc
AAA Authentication, Authorization and Accounting entity. See RADIUS and Diameter
AAL AAL Adaptation Layer
ABNF Augmented BNF. Defined in RFC 2234
ABR Average bit rate
ABS Alternate Billing Service
AC Authentication Centre. Stores information for authenticating mobiles, and encrypting their voice and data transmissions
ACC Analog Control Channel. See FSK
ACCM Asynchronous Control Character Map
ACCOLC Access Overload Class
ACCT CDMA Access Control by Call Type
ACD Automatic Call Distributor. Distributes incoming calls to one of a number of people equally able to handle them (e.g. for customer service)
ACELP(1) Adaptive CELP
ACELP(2) Algebraic CELP
ACF Authentication Control Function
ACG Automatic Code Gapping. A method of shedding load in telecommunications systems
ACH Access Channel
ACK Acknowledgement signal
ACLR Adjacent Channel Leakage Ratio. The ratio of the on-channel transmit power to the power measured in one of the adjacent channels. An important W-CDMA parameter.
ACM SS7 ISUP Address Complete message. Response to IAM
ACP Adjacent Channel Power
ACRE Authorization & Call Routing Equipment. Used for routing calls to cellular phones with a ‘cordless’ mode
AD(1) Abbreviated Dialing
AD(2) Architecture Document
ADA Advertising Agent. Provides information to a MS on the services provided by a 3G network
ADDS Application Data Delivery Service. See SMS
ADF(1) Application DF.
Adjacent Channel Interference Interference from signals at slightly different frequencies
ADN Abbreviated Dialing Numbers
ADPCM Adaptive Differential PCM
ADRC Aggregate Data Rate Caveat. A warning that most wireless data rates are aggregate, meaning that all users share the bandwidth, and often they are raw rates higher than the actual user throughput could ever be even on an unloaded system. It is probably good to start by dividing the raw rate by a factor of two to obtain the total user throughput rate and then further divide by the average number of simultaneous users (not connected users, but the number who are likely to be simultaneously transmitting)
ADS Asynchronous Data Service
ADSL Asymmetric DSL. Bit rates are higher from the network than from the client
AdSpec IETF Advertisement Specification
AEG Asian Expert Group. A WAP Working Group
AES Audio Engineering Society
AF Application Function.
AFLT Advanced Forward Link Trilateration. A geolocation technique that utilizes the mobile station’s measured time of arrival of radio signals from the base stations (and, possibly, other terrestrial measurements)
AFRCN GSM Absolute radio frequency channel number
AFSK Audio FSK. Communication by changing frequencies in the audio band rather than RF. Used by MF, DTMF
AGCH GSM Access Grant Channel. The traffic channel assignment information is sent to the mobile on this channel.
AGPS Network Assisted GPS. Land station assists mobile in acquiring its position
AGW Access Gateway
AH(1) Authentication Header
AH(2) Answer Hold. Service that allows an incoming call to be placed on hold without answering it first. Closely related to USCF
AHAG TIA TR-45 ad hoc Authentication Group
AI Air Interface
AICH Acquisition Indicator Channel
AID(1) ISO/IEC 7816 Application Identifier composed of RID and PIX.
AIN Advanced Intelligent Network. Telcordia version of IN
Air Interface Synonym for Radio Interface.
AK Anonymity Key. In AKA it is derived from RAND using f5.
AKA Authentication and Key Agreement. New generation of security being developed for 3GPP2 CDMA systems and 3GPP UMTS systems. Parts may also be applied to GSM
Alert A command to a mobile to notify the user of an incoming call or message
ALG(1) Application Layer Gateway. A device within the internet that performs special functions for a specific application layer protocol (e.g. instant messaging, VoIP, email).
ALI Automatic Location Information. A database that contains information about the location of emergency callers
AM Amplitude Modulation. See FM
AMA Automatic Message Accounting. See CDR
AMF AKA Authentication Management Field. May indicate the algorithm and key used by the current authentication system.
AMI Alternate Mark Inversion
AMPS Advanced Mobile Phone Service. TIA analog cellular, and all standards that retain compatibility with it (NAMPS, D-AMPS, CDMA). Standardized in EIA/TIA-553
AMR Adaptive MultiRate Voice Coder. Proposed for use in GSM and UMTS. Bit rates vary between 12.2 and 4.75 kbps
AMR-WB AMR wide (audio) band Voice Coder chosen for UMTS. Developed by Nokia and Voiceage. Has 9 different bitrates
AMTA American Mobile Telecommunications Association
AN Access Network
analog Transmission of information through a continuously variable signal. Compare with digital
analogue Alternate (British) spelling of analog
Anchor MSC The first MSC involved in a wireless call
ANI(1) Automatic Number Identification. Provision of charge number during a call to allow toll calls without operator intervention
ANI(2) Access Network Identifier
ANI II ANI Information Digits. Describes the type of phone being used to call (e.g. residential line or payphone).
ANM SS7 ISUP Answer Message
ANSI American National Standards Institute
ANSI-136 ANSI version of the TDMA air interface standard. Replaces IS-136. Correct name is TIA-136
ANSI-41 See TIA/EIA-41
ANT ADSL Network Termination
AOA Angle of Arrival. A technique for locating a radio by estimating the angle of signal arrival at multiple points. Compare with TOA
AoC Advice of Charge
AP(1) Application Part (of a protocol)
AP(2) Access Point. An 802.11 BS
APCO Association of Public Safety Communications Officials
APDU Application PDU
API Application Programming Interface
APLMN Associated PLMN
APM Application Transport
APMN Associated PMN
APN Access Point Name. In a GPRS network, the domain name referring to an external packet network
ARCH Access Response Channel
ARIB Association of Radio Industries and Businesses. Responsible for standardization of telecommunications protocols in Japan
ARM ARQ Response Mode
ARP(1) Authorized Receipt Point. The sole entity authorized to settle and exchange roamer charges and revenue for a carrier
ARP(2) IETF Address Resolution Protocol. Binds the physical (MAC) address of a device to an IP address on a local network (e.g. ethernet subnet).
ARPU Average Revenue Per User/Unit
ARQ Automatic Repeat Request. A method of error correction where the receiver detects errors, and requests retransmission from the sender.
AS Internet Application Server. Handles applications for a range of addresses (e.g. a telephone switch)
ASCII American Standard Code for Information Interchange. The most commonly used method for encoding text in 8 bit characters. See UNICODE for more complex alphabets and the obsolete EBCDIC
ASE Application Service Element
ASIC Application Specific Integrated Circuit. A computer chip that is customized for a special purpose application
ASN.1 Abstract Syntax Notation 1. A formal, textual, representation of a protocol message set
ASP AS Process
ASR Automatic Speech Recognition
Assisted GPS(1) A class of GPS receiver that uses information from another source to make positioning quicker. This is common in cellular phones, where the cellular BS transmits additional information to make the acquisition of satellites quicker and may offload some of the calculations.
Asynchronous Data is transmitted only when needed. At least one bit is needed to indicate the start of transmission (known as a start bit). Compare with Synchronous
AT Access Tandem. A switch that can be used to reach a variety of IXCs
ATCA(1) Advanced Telecommunications Computing Architecture. A board and shelf design for telecommunications and other ruggedized applications. Developed by PICMG.
ATI Access Terminal Identifier
ATIS Alliance for Telecommunications Industry Solutions. Parent organization for the T1 standards committees and many telecom industry groups, such as OBF
ATM Asynchronous Transfer Mode. Transmits data as 53 byte units using a connection-oriented protocol at speeds up to 2.488 Gbps
ATP Access Transport Parameter (also Adenosine Tri-Phosphate :)
ATS Abstract Test Suite
AuC GSM term for AC
AUTH An OMT bit that turns mobile authentication on or off for all mobiles within a cell
AUTHBS Authentication Response from the BS
Authentication Proving the identity of an individual or application (e.g. MS)
Authentication Enhancements Improvements to network based authentication (TIA/EIA-41) defined in IS-778
Authentication Vector See Quintet and Triplet
AUTHR Authentication Response. The output of CAVE when RAND is used as a global challenge
AUTHU Authentication Response to Unique Challenge
AUTN AKA Network Authentication Token. Composed of SQN (concealed), AMF and MAC
AV Authentication Vector
AVC Analog Voice Channel
AVP Attribute Value Pair. A method of encoding parameters that includes the length of the data, the attribute (parameter) type (usually fixed length) and the attribute value. cf TLV
AWGN Additive White Gaussian Noise
AWI Alert with Information; used to transmit data while alerting an MS
AWS An FCC term for IMTS-2000


B-SMS Broadcast SMS
B/I Busy/Idle bit
B8ZS Bipolar with 8 Zero Substitution. Replaces an all-0 octet by one containing two BPV
Baby Bell see RBOC
Backhaul Routing trunks from a cellsite to an MSC before routing to the PSTN.
badput A cute name for wasted bandwidth. Bandwidth = goodput(throughput) + badput + unused bandwidth
BAF Billing Automatic Message Accounting Format. The CDR/AMA format used by most US wireline telecom carriers
BAIC Barring of All Incoming Calls
BAOC Barring of All Outgoing Calls
BARG GSMA Billing, Accounting and Roaming Group
Barring Refusal to allow certain types of calls
Baseband The signal(s) used to modulate the radio channel in the transmitter, and which are recovered by the receiver by demodulating the received radio channel.
BATS Broadcast Air-interface Transport Service used by TIA/EIA-136
BBIT Best Breakfast In Town.
BCCH Broadcast Control Channel
BCD Binary Coded Decimal. Digits 0-9 are encoded as 4 bit numbers (nibble), so two fit within a byte. See TBCD
BCE Base Station Central Equipment. See BSC
BCH(1) Broadcast Channel. A channel transmitted by one (e.g. BS) and received by many (e.g. MS)
BCH(2) Bose, Chaudhuri, and Hocquengham error detection and correction methodology
BCH(3) Basic Call Handling
BCM Basic Call Manager. See WIN
BCMCS Broadcast/Multicast Services for 3GPP2. Contrast with BMC
BCSM Basic Call State Model. A n IN concept
BD Billing Domain
BDN Barred Dialing Number
Bearer capability A capability of a transport protocol (e.g. a maximum bitrate or message latency). A Teleservice may be able to use any facility that can provide a specified bearer capability.
BEG Billing Expert Group. A WAP Working Group
Beidou(1) A Chinese GNSS.
BER(1) See Bit Error Rate
BER(2) Basic Encoding Rules. See ASN.1
BGCF Breakout Gateway Control Function. Controls the assignment of resources to IMS sessions in a serving system. Connected to the S-CSCF, MGCF and BGCF
BGP Border Gateway Protocol of IETF RFC 1771. See EBGP.
BIB Backward Indicator Bit. Indicates when a received MTP frame is out of sequence. See FIB
BIC-Roam Barring of Incoming Calls while Roaming
BICC Bearer Independent Call Control. ISUP adapted for use over IP-based transport. Compare with SIP
BID A SID allocated for accounting purposes. BID's are allocated by Cibernet
BIP(1) Bearer Independent Protocol. A method for transferring SIM, USIM, ISIM or CSIM configuration data over the high speed interface of a phone, e.g. GPRS or EvDO, instead of the previous, much slower, SMS method. Defined in ETSI TS 102 223
BISDN Broadband ISDN
bit Fundamental unit of information, occupying two discrete states (e.g. 0 or 1)
Bit Error Rate The fraction of binary bits that are received with the wrong value.
BLA SS7 ISUP Blocking acknowledgement. See BLO
BLOB Block of Bits
Bluetooth A cable-replacement radio protocol for short distance (5-100 meter) networking at moderate speeds (1 Mbps raw bandwidth for version 1 and 3 Mbps for version 2). Developed by the Bluetooth Consortium and standardized by IEEE 802.15.1
BLV Busy Line Verification
BM-SC Broadcast/Multicast Service Center
BMC Broadcast Multicast Control. See 3GPP TS25.324. Contrast with BCMCS.
BMI BS, MSC and Interworking function
BNF Backus-Naur Form. A precursor to ASN.1 and other meta-language
BNS Billed Number Screening
BOC Bell Operating Company
BOIC Barring of Outgoing International Calls
BOIC-exHC BOIC except to HC
Border Router An IP Router that connects to routers in other networks using the EBGP protocol.
BP Bit Position
bps Bits per second. A measure of the speed of a transmission link
BPSK Biphase Shift Keying
BPV Bi-Polar Violation. Transmission of two one-bits in a PCM channel (e.g. DS0) with the same polarity (e.g. both positive or both negative). May be deliberately used to indicate all-zero octets. See B8ZS and HDB3
BR Border Router. Connects a CN with peer networks
BREW Binary Runtime for Wireless
BRI Basic Rate Interface (64 kbps). See DS0
Broadcast SMS Short messages sent to multiple mobiles in multiple cells, requiring only one message per cell
BS Base Station (includes BTS and BSC)
BSC Base Station Controller. The 'brains' of a base station, controlling the radio equipment in the BTS
BSF Bootstrapping Function
BSIC BS Identity Code. Color code used by GSM systems to ensure that the source of a frequency transmission can be identified, in areas where multiple cells transmitting on the same frequency can be received
BSMC Base Station Manufacturer Code
BSN(1) Backward Sequence Number. The sequence number of the last correctly received MTP frame received. Contrast with FSN
BSN(2) BCMCS Serving Node
BSS(1) BS Subsystem
BSS(2) Basic Service Set. An 802.11 network.
BT Burst Type
BTA Basic Trading Area
BTS Base Transceiver System (radio portion of BS)
BTTC Broadcast SMS
BWIF Broadband Wireless Internet Forum. A program of IEEE-ISTO
BXA US DoC Bureau of Export Administration. Administers EAR
byte An 8 bit unit of data storage. See octet


C-PDS cdma2000 Packet Data Service
C/I Carrier to Interference Ratio
C7 See CCS7
CA(1) Certificate/Certification Authority
CA(2) Collision Avoidance
CAC Carrier Access Code. Identifies a long distance carrier. 101+CIC
CALEA US Communications Assistance for Law Enforcement law. Requires that telecommunications carriers provide for surveillance (aka wiretaps) at the switch site
CAMA Centralized Automatic Message Accounting
CAMEL Customized Applications for Mobile Networks Enhanced Logic based on CAP. IN capabilities for GSM. Compare with WIN
Candidate MSC An MSC being considered as the Target MSC of a handoff
CAP(2) Carrierless Amplitude and Phase modulation
CAP(3) Competitive Access Provider
CAPCS Cellular Auxiliary Personal Communications Service
CAR Committed Access Rate. An IP method to achieve higher QoS
CARE Customer Account Record Exchange. Sent from a LEC to an IXC to establish a long distance account for a customer
Care-of Address The address that a Home Agent forwards packets to for handling by the Foreign Agent in MIP
Carnivore US FBI ISP wiretapping box, including a processor and removable hard drive to capture internet sessions (email, web access etc.).
CAS Call Associated Signaling. See ISUP. Contrast with NCAS
CAT Smart Card Application Toolkit
CATPT CDMA UIM Card Application Toolkit Protocol Teleservice
CATR(1) China Academy of Telecommunication Research of MII. A government owned research institute that participates in the development of standards. Formerly RITT.
CAVE TIA Cellular Authentication and Voice Encryption Algorithm
CB Cell Broadcast
CBC CB Center
CBMI CB Message Identifier
CBR Constant Bit Rate
CBS GSM/W-CDMA Cell Broadcast SMS
CC(1) E.164 Country Code
CC(2) GSM Call Control protocol
CC(3) Content of Communications (for LAES)
CCA Common Cryptographic Algorithm
CCAT CDMA Card Application Toolkit. Specifies communications between a CDMA R-UIM and the ME.
CCB US FCC Common Carrier Bureau
CCBS Call Completion to Busy Subscriber
CCCH GSM Common Control Channels – PCH, RACH, AGCH
CCF(1) Call Control Function (IN term)
CCF(2) Charging Collection Function (3GPP)
CCH Control Channel
CCITT International Telegraph and Telephone Consultative Committee. Precursor to ITU. See ITU-T and ITU-R
CCNR Call Completion on No Reply. See CFNA
CCP Compression Control Protocol
CCPD Common Channel Packet Data
CCPN Call Completion to a Ported Number. See LNP
CCPU(1) Cash Cost Per User. The cost of operating a telecom business on a per-user basis. It does not include capital costs.
CCR(1) SS7 ISUP Continuity check request
CCR(2) Class Conformance Requirement
CCS Common Channel Signaling
CCS7 ITU-T version of SS7
CCSA China Communications Standards Association. Successor to CWTS.
CCSC Cellular Carrier Specific Code (e.g. #123)
CCSH CDMA Code Combining Soft Handoff
CCSS Call Completion Service Setup
CCT Circuit
CCV Credit Card Validation
CCW Cancel Call Waiting
CD Collision Detection
CDATA Character Data, such as a quoted text string. Used in XML and derivative protocols such as WML
CDCP Call Detail Collection Point. See TIA/EIA-124
CDG CDMA Development Group
CDGP Call Detail Generation Point
CDIS Call Detail Information Source. An MSC or other entity that produces proprietary CDR’s
CDMA Code Division Multiple Access. Implemented in AMPS-compatible systems by IS-95. Also see W-CDMA
CDMA-PAMR A CDMA-based PAMR system.
cdma2000 Trade name for CDMA air interface standards aimed at 3G requirements, including IS-2000. It operates in 1.25 MHz carriers at 1.2288 Mcps. There is some debate about whether the "CDMA" should be upper or lower case :)
cdmaOne Trade name for first generations of CDMA air interface standards, including TIA/EIA-95. Operates in pairs of 1.25 MHz channels
CdPA Called Party Address
CDPD Cellular Digital Packet Data. A protocol that uses 30 khz AMPS channels to transmit packets of data. Standardized in TIA/EIA/IS-732
CdPN Called Party Number. The DN of the party receiving a call
CDR Charging Data Record or Call Detail Record
CDRP Call Detail Rating Point
CDVCC Coded Digital Verification Color Code
CEASA Cellular Emergency Alert Systems Association. Promotes the use of emergency alerts over cell phones.
CEG Carrier Expert Group. A WAP Working Group
cell The coverage area of a single radio cellsite or sector in a cellular or PCS system
cellular A radio concept that allows the multiplication of capacity by using many low-power cell to cover an area, reusing frequencies as much as possible
CELP Code Excited Linear Prediction
CENELEC European Committee for Electrotechnical Standardization
CEP Cell Equipment Processor
CEPT Conference des administrations Europeannes des Postes et Telecommunications
CEWS Cell Work Station. Software running here supports termination of the LAPD links to the BTS. A minimal OA&M application is included to support maintenance of the A-bis interface processes and to route OA&M messages to/from the BTS. Call Handling software derives directly from the CEP and PPP of the BCE.
CF Collection function. LEA that collects J-STD-025 data
CFB Call Forwarding when subscribing telephone is busy
CFNA Call forward on no-answer (and, usually, also on no page response). See CFNRc and CFNRy
CFNRc Call forward when mobile not reachable. See CFNA
CFNRy Call forward when mobile is not answered. See CFNA
CFU Call Forwarding Unconditional (i.e. every incoming call will be forwarded)
CG Charging Gateway
CGB SS7 ISUP Circuit group blocking
CGBA SS7 ISUP CGB acknowledgement
CGI(1) Common Gateway Interface
CGI(2) GSM Cell Global Identification. Composed of LAI + CI
CGL Calling Geodetic Location. The position of a mobile phone, as transmitted through various signaling protocols. See GAD
CGLP SS7 ISUP Calling Geodetic Location Parameter (i.e. Latitude and Longitude)
CgPN Calling Party Number. The DN of the party initiating a call
CGSA Cellular Geographic Serving Area. MSA or RSA
CGU SS7 ISUP Circuit group unblocking
CGUA SS7 ISUP CGU acknowledgement
CGVoP Carrier Grade Voice over Packet. See VoIP
CHAP PPP Challenge Handshake Authentication Protocol. Use of RADIUS to authenticate a terminal without sending security data in the clear. Compare with PAP
cHTML Compact HTML. Use by iMode. See also WML and XHTML
Churn The rate at which subscribers leave one wireless carrier to go to another. A major expense for carriers
CI GSM Cell Identity. A 16 bit number identifying a cell within an LAI
CIBER Cellular Intercarrier Billing Exchange Record. Format used for exchange of wireless billing records. Maintained by Cibernet Corp
Cibernet A subsidiary of Mach Corporation, originally formed by the CTIA to facilitate billing aspects of roaming such as net settlement and exchange of CIBER billing records.
CIC Carrier Identification Code. See CAC
CIDR(1) Classless Inter-Domain Routing. A method of allocating IPv4 addresses that is not Classful but allows a 32-bit IPv4 address to be broken on any bit boundary. This is still not as flexible as assigning addresses as arbitrary ranges of numbers but simplifies analysis by allowing bit-masking. See Wikipedia.
Ciphertext Encrypted data. Compare with Plaintext
CIR(1) Synonym for C/I
CIR(2) Committed Information Rate. Bandwidth associated with a frame relay PVC
Circuit-switched data Data transmitted over a dedicated (although usually virtual) channel. The destinatioin address is implicitly defined by the (virtual) circuit that is selected
CISC CRTC Interconnection Steering Committee
CITEL Commission InterAmericanna de Telecommunications Association. A Latin American telecommunications association
CK Cipher Key. In AKA, it is derived from RAND using f3 and applied to traffic using f8
CKSN CK Sequence Number
CLASS Custom Local Area Signaling Services. A package of features offered by wireline carriers
Clearinghouse A central point for the gathering and redistribution of records, such as billing records
CLEC Competitive LEC. A new entrant in a market previously limited to one carrier. Some wireless carriers may qualify for this designation
CLI Calling Line Identity. See CgPN
CLIP Calling Line Identification Presentation. See CNIP
CLIR Calling Line Identification Restriction. See CNIR
CLLI Common Language Location Identifier. An ASCII identifier of a telephone switch or calling area.
CLNP Connectionless Network Protocol
CLNS Connectionless Network Service
CM GSM Connection Management
CMAC Control Mobile Attenuation Code
CMC Cellular Mobile Carrier. A generic term used to classify carrier class cellular systems
CMEA Cellular MEA. Based on CAVE
CMIP Common Management Information Protocol
CMRS Commercial Mobile Radio Service
CMSP Indian GSM licence. Replaced by UASL.
CMT Cellular messaging teleservice. A service based on SMS that is similar to that provided by alphanumeric pagers
CMWN Cancel Message Waiting Notification
CN Core Network. Protocols for this include GSM MAP and ANSI-41
CNA Canadian Number Administrator. Administers telecom numbering resources in Canada, under the oversight of the CRTC.
CNAME Canonical Name. A basic Domain name that may be pointed to by multiple aliases
CNAP Calling NAme Presentation. A terminating party feature. Overridden by CNAR
CNAR Calling NAme Restriction. An originating party feature
CNDB Calling Name Database
CNIP Calling Number Identification Presentation. A terminating party feature. Overridden by CNIR
CNIR Calling Number Identification Restriction. An originating party feature
CO Central Office
Co-channel Interference Interference from other signals using the same radio channel
COA Care-Of Address
CoAP(1) IETF Constrained Application Protocol. A fairly efficient method for encapsulation of binary data, designed for M2M applications, defined in an internet draft. It assumes that every device has an IP address.
codec Voice coder and decoder. See vocoder and Voice Coder
COFETEL Comision Federal de Telecomunicaciones de Mexico
COLP Connected Line Identification Presentation. See COLR, CNIP
COLR Connected Line Identification Restriction. See CNIR, COLP
COMET IETF SIP Preconditions Met message
Confidentiality Keeping information private (e.g. by encryption)
CONS Connection-Oriented Network Service
Control Channel A cellular or PCS channel that broadcasts information about a cell to mobiles that are not currently in a call
CORBA Common Object Request Broker Architecture
CORD Cellular Operations Record Distribution
CoS Class of Service. Method of managing traffic by grouping similar types (e.g. voice, video, email)
COTP(1) Connection-Oriented Transport Protocol. Specified by ISO 8073. An alternative to TCP that is packet-based rather than stream-based, meaning that the transport protocol, rather than the application protocol, keeps packets of data separate. Despite this, most systems use TCP with the ITOT protocol on top if necessary. Port 102 is reserved for use by this protocol.
COUNT Call History Count. An internal mobile counter that can be used to detect the presence of clones
COWS Common Work Station. Software running in the Common Work Station element supports termination of the SS7 links to the MSC as well as the X.25 links to the OMC (including the OSI stack) and any PSDN services. The majority of the OA&M software is found here.
CPDE Centralized PDE
CPE Customer Premises Equipment. A standard telephone is an example of telecommunications equipment that is usually located at the customer’s site.
CPG SS7 ISUP Call ProGress Message
CPGA Cost per Gross Addition. The cost to a carrier of adding one subscriber
CPL IETF Call Processing Language. An XML-based language for describing internet telecommunications services.
CPP Calling Party Pays. The calling party pays for calls to mobile, not the mobile receiving the call. cf TPP
CQM(1) Channel Quality Measurement
CQM(2) Core Quality of Service Manager. Obsolete. See PDF
CR Change Request. A description of a problem in a standard (error, limitation, ambiguity or restriction) and a description of how it should be fixed
CR-LDP Constraint-based Routing LDP. See MPLS
CRC Cyclic Redundancy Code (or check). Included in many digital protocols to check for errors in transmitted messages
CRDB Coordinate Routing DataBase. Proposed for E911 systems to convert a location into routing information
CRL Certificate Revocation List
CRM(1) Customer Resource Management
CRM(2) Channel Request Message
CRTC Canadian Radio-television and Telecommunications Commission
CRTP Compressed Real-Time Transport Protocol. Provides compression (and decompression) of RTP, UDP and IP headers.
Cryptosync Externally-provided synchronizing information for cryptoalgorithms (ciphers) that allows an encryptor at one end to uniquely encrypt each block of content into ciphertext, and yet allows a decryptor at the other end to properly decrypt the ciphertext to yield the original plaintext. Cryptosync often takes the form of the output of a binary counter
CS(1) IN Capability Set
CS(2) Circuit switched. Contrast with PS
CS-1 IN CS 1
CS-2 IN Capability Set 2
CS-ACELP Conjugate Structure ACELP
CSA Canadian Standards Association
CSC Customer Service Center
CSCF Call Session Control Function. Controls the assignment of resources from the home system. See I-CSCF, P-CSCF and S-CSCF
CSCN Canadian Steering Committee on Numbering. A working group of the CRTC CISC
CSD Circuit switched data. Data travels between two devices using a fixed amount of bandwidth allocated for the duration of the data call. Compare with Packet data that uses shared bandwidth to service multiple users. Packet data can be more efficient (except when the overhead of identifying and routing packets is greater than the savings) but the performance is less predictable.
CSFP Coded Superframe Phase
CSI CAMEL Subscription Information
CSIM(1) cdma2000 Application on UICC. Defined in 3GPP2 TSG-C specification C.S0065.
CSMA Carrier Sense Multiple Access
CSMA/CD CSMA with CD (also known as CA). Ethernet devices use this to minimize collisions by checking the line before sending
CSRC Contributing Source
CSS Cascading Style Sheets. See HTML
CSU Channel Service Unit. Unit that interfaces between the telephone company and a private network
CT Call Transfer
CTCP Compressed TCP. Provides compression (and decompression) of TCP and IP headers.
CTIA Cellular Telecommunications Industry Association
CUG Closed User Group. Calls are restricted to within the group
CW Calling Waiting
CWTA Canadian Wireless Telecommunications Association
CWTS Chinese Wireless Telecommunications Standards. Replaced by CCSA


D Digit The fourth digit of an NANP phone number. Currently restricted to the values 2-9 to allow 7 digit dialing
D-AMPS Digital AMPS (IS-54 and IS-136 TDMA)
D-H Diffie-Hellman
D/L Downlink (e.g. from base station to mobile). Compare with U/L.
DAP X.500 Directory Access protocol
DataTAC Data TAC. A Motorola wireless data system. Formerly known as Ardis.
dB Decibel. 10 times the logarithm of the value in base 10
dBi Decibels relative to isotropic radiator. A measurement of the gain of an antenna.
dBm Decibels referenced to one milliwatt
DCC Digital Color Code. A number assigned to a control channel used to limit erroneous accesses
DCCH Digital Control Channel. The control channel used by IS-136 and TIA/EIA-136 D-AMPS systems
DCE Data Communications Equipment (i.e. a computer)
DCF DRM Content Format
DCH Dedicated Channel
DCN Data Communications Network
DCS(1) Data Coding Scheme
DCS(2) Digital Cross-Connect System
DCS(3) European PCS frequencies in the 1800 MHz range.
DDM Data Description Method
DEA US Drug Enforcement Agency
DECT Digital Enhanced Cordless Telephony
DES Data Encryption Standard. A commonly used encryption method, usually used with 56 bit keys. See AES, TDES.
DF(1) UIM Dedicated File. Compare with EF and MF
DF(2) Delivery Function (for LAES)
DFCA Dynamic Frequency and Channel Allocation. Dynamic assignment of radio channels to optimize capacity. Proposed for GSM, but not yet implemented.
DFP Distributed Functional Plane NRM
DHCP Dynamic Host Control Protocol. Allows automatic assignment of IP addresses on a network
DHKE Diffie-Hellman Key Exchange. A method of securely exchange encryption keys over an insecure interface
Diameter An IETF AAA protocol designed to be twice as good as RADIUS. Unlike its predecessor it supports MIP and uses SCTP (or TCP) instead of UDP for more reliable transport. It uses IPSEC and TLS instead of a shared secret.
DID Direct Inward Dialing. Directs all calls to a block of numbers to a PBX
Diffie-Hellman A secure key exchange mechanism
Diffserv Differentiated Services. Different QoS for different types of traffic (e.g. voice, video, email). See IETF RFCs 2474 and 2475
digital Transmission of information through a signal that can take on only certain discrete values (e.g. bits with values 0 or 1). Compare with analog
Disconnection The end of a call. Not to be confused with Termination of a call or the Release of a trunk
DL Downlink. Radio link from network ‘down’ to terminal. Compare with UL
DLC Digital Loop Carrier. A single digital facility (e.g. T1 or T3) carrying multiple lines to a business or other large customer
DLCI Data Link Connection/Circuit Identifier
DLP Discrete Logarithm Problem. Used in some cryptography systems
DMAC Digital Mobile Attenuation Code
DMH Data Message Handler. An informal name for the TIA IS-124 standard
DMO Direct Mode Operation. Group calling capabilities, e.g. PTT, of a PAMR system. Compare with TMO.
DMT Discrete Multi-Tone line code being proposed for VDSL. Compare with QAM/CAP
DMU Dynamic MIP Key Update. A secure and efficient mechanism for distributing and updating Mobile IP (MIP) cryptographic keys in cdma2000 networks (including High Rate Packet Data which is often referred to as 1xEV-DO). Because the Dynamic Mobile IP Key Update (DMU) procedure occurs at the IP layer directly between the MIP MN and RADIUS or Diameter AAA Server, it may be used to securely bootstrap the MN-AAA key (and other cryptographic keys) in MIP networks using any RAN technology.
DN(1) Directory Number. The number dialed to terminate a call to a phone
DN(2) Domain Name (e.g.
DNIC Data network identification code
DNIS Dialed Number Identification Service. Identifies the called (not calling) number. Only useful when multiple numbers terminate at the same location (e.g. a regular phone number, 1-800 and 1-900 number). Contrast with CNIP
DNS Internet Domain Name Service/System. See RFC 1035
DOA Dead On Arrival
DoC US Department of Commerce
DOI Domain of Interpretation
DOJ US Department of Justice
Domain A portion of the internet (e.g.
Donor Switch The switch from which a number has been ported. See LNP
Downlink Path from base station to terminal
DP WIN/CAMEL Detection Point
DPC(1) Destination Point Code for an SS7 message
DPC(2) Downlink Power Control
DPCCH Dedicated Physical Control Channel
DPCH Dedicated Physical Channel
DPDCH Dedicated Physical Data Channel
DPSK Differential PSK
DQPSK Differential Quadrature PSK
DRAC Dynamic Resource Allocation Control
DRM Digital Rights Management
DS Direct Spread. See CDMA
DS-CDMA Direct Sequence CDMA
DS0 Digital Signal Level 0. A 64 kbps digital link used to carry a single voice conversation or signaling traffic for multiple calls/trunks. In ANSI networks, 8 kbps is usually reserved for in-band signaling (on-hook/off-hook etc.), reducing the bandwidth to 56 kbps
DS1 Digital Signal Level 1. A 1.544 Mbps signaling link carrying 24 DS0 channels
DS1C Digital Signal Level 1C. A 3.152 Mbps signaling link carrying 48 DS0 channels
DS2 Digital Service, Level 2. 6.312 Mbps. Carries 96 DS0 channels (4 DS1 channels)
DS3 Digital Service, Level 3. 44.736 Mbps. Carries 672 DS0 channels (28 DS1 channels)
DSA Digital Signature Algorithm
DSCH Downlink Shared Channel
DSF Dispersion Shifted Fiber
DSI Digital Speech Interpolation
DSL Digital Subscriber Line. See SHDSL, ADSL, SDSL, VDSL
DSLAM DSL Access Multiplexer
DSMA Digital Sense Multiple Access. Access to a shared resource is controlled by sensing a digital signal before attempting an access. Used by CDPD
DSP Digital Signal Processing/Processor
DSR(1) Distributed Speech Recognition
DSR(2) Direct Signal Reporting
DSS-1 Digital Subscriber Signaling System No. 1
DSU(1) Digital Service Unit. Interface between the terminal equipment (DTE) and the service provider's facilities
DTC Digital Traffic Channel
DTCH Dedicated Traffic Channel
DTD Document Type Definition. An XML grammar specification
DTE Data Terminal Equipment
DTM Dual Transfer Mode. Simultaneous voice and data connections with GSM and EDGE, bringing some 3G services to a 2G system (without the wide pipe though!)
DTMF Dual Tone Multifrequency. Tone signaling used by phones
DTN Deflected-To Number
DTX Discontinuous Transmission. A mobile only transmits when the user is talking. This saves battery life, but can introduce some choppiness into conversations
Dual-band A mobile that can support two different frequency ranges. Compare with Dual-mode
Dual-mode A mobile that can support two different technologies. Compare with Dual-band
DUP SS7 Data User Part
DVCC Digital Verification Color Code
DWDM Dense Wave Division Multiplexing


E-GGSN Enhanced GGSN
E-Mail(1) Electronic Mail
E-OTD Enhanced Observed Time Difference. A positioning technology based on software within wireless phones combined with their existing signal measurement capabilities. Compare with the purely network-based AOA, TOA and TDOA
E-SMR Enhanced SMR. See iDEN
E.118 The ITU-T recommendation for ICCID.
E.164 ITU-T dialing plan standard. Numbers are composed of CC+NSN (NDC + NDC)
E.212 ITU-T mobile identification number standard
E.214 ITU-T standard that allows an E.212 IMSI number to be mapped onto an E.164 number to allow routing through SS7 networks. Unfortunately, this mapping does not work in North America
E1 A digital link carry 32 DS0 channels, with two used for signaling purposes. Used mostly outside North America. Compare with T1
E911 Enhanced 9-1-1 service. Provides the identity and the approximate location of the calling phone
EA(1) Economic Area. A geographical area used by the US FCC to license the AWS A band.
EA(2) Equal Access
EACC Emergency Area Congestion Control
EAP IETF Extensible Authentication Protocol, RFC 4017
EAP-TLS EAP Transport Layer Security. Public key encryption for WiFi.
EAP-TTLS EAP Tunneled Transport Layer Security. Provides mutual authentication of WiFi network and client through the use of network-side certificates.
EAR Export Administration Regulations. Replace ITAR for control of export of encryption technologies
EAS Emergency Alert System. A US government system that transmits audio or text information about emergencies (mostly weather) to radio and TV stations. There has been some talk about extending this to wireless phones via broadcast SMS
Eb Energy of an information bit
EBCDIC Extended Binary Coded Decimal Interchange Code. IBM's byte code for letters, numbers and special characters. Not as good as ASCII because, for example, letters are not all in a single group, making software more awkward
EBGP External BGP. BGP between routers in two different networks.
EBNF Extended BNF. Used to define XML, for example.
EBS Emergency Broadcast System. See EAS
EC Exchange Carrier
ECC Elliptic Curve Cryptography
ECDLP Elliptic Curve Discrete Logarithm Problem. See ECC
ECMA European Computer Manufacturer's Association
ECSA Exchange Carrier's Standards Association. Renamed ATIS several years ago
ECT Explicit Call Transfer
EDAC CDMA Error Detection and Correction coding. See FEC
EDGE Enhanced Data-rates for GSM (or Global) Evolution. Uses 8PSK modulation to increase data rates within the 200 kHz RF bandwidth to a theoretical limit of 384 kbps (474 kbps raw), although per-user rates will be significantly lower because few if any phones can use all 8 available timeslots. A higher speed successor to GPRS. See ADRC
EDI Electronic Data Interchange. Used to transfer business-level data between companies (e.g. invoices, purchase orders). Nowadays, more attention is on XML for this purpose
EDR Efficient Data Representation. Assigns one record to represent a block of 1,000 pooled numbers
EDS Enhanced Dialed Service(s)
EESN Expanded ESN. An idea for a 56-bit identifier to replace ESN that never took off. See MEID and EUIMID.
EF UIM Elementary File. Compare with DF and MF
EFI External Functionality Interface
EFR Enhanced Full Rate. The standard GSM Voice Coder operating at 12.2 kbps
EGNOS(1) European Geostationary Navigation Overlay System. A WAAS to augment GPS and GLONASS in Europe.
EGPRS-136 GPRS adapted for use in TIA/EIA-136 networks
EHFC Extended Hyperframe Counter
eHRPD(1) Evolved HRPD. An HRPD system using the 3GPP EPC and providing an evolutionary path to cdma2000 operators.
EIA Electronics Industry Alliance
EIA/TIA-553 Analog AMPS cellular standard. Formerly IS-3
EIR Equipment Identity Register. Stores information about wireless terminals as opposed to subscriptions. Compare with HLR
EIRP Effective Isotropic Radiated Power
ELCA Extended Local Calling Area. Allows toll-free calls to numbers outside the normal toll-free zone, by arrangement with the terminating (usually wireless) carrier
EMA Electronic Messaging Association.
EMC Electro-Magnetic Compatibility
EMF Electro-Magnetic Field or Electro-Motive Force (Voltage)
EMI Exchange Message Interface. A LEC billing record format. Compare with EMR. Contrast with BAF and CIBER
eMLPP Enhanced MLPP. A GSM method for implementing PS
EMR Exchange Message Record. A LEC billing record format. Compare with EMI. Contrast with BAF and CIBER
EMS Enhanced Messaging Service. SMS extended to include simple graphics, audio and enhanced text (e.g. fonts). A precursor to MMS
EMTEL Emergency Telecommunications for ETSI
EN European Norm (Standard).
enum Telephone Number Mapping to an internet address. A method of converting a phone number into a domain name defined by IETF RFC 2916. Take the full number (including country code), reverse it, put a dot between each pair of adjacent digits, append '' and, there you have it! This format is easier for DNS systems to handle.
EO End Office
EOM End Of Message
EP SCP ETSI Project Smart Card Platform
EPC(1) Evolved Packet Core. Core network for LTE.
EPE Enhanced Privacy and Encryption. A North American TDMA architecture that secures voice, messages, and data through encryption
Ephemeris(1) Information on GPS satellite orbits, used to make the acquisition of satellites more efficient.
Erlang Measure of traffic load. Calculated as rate at which calls arrive divided by the rate at which they are completed
Erlang B A traffic model used to engineer resource groups when blockage is low, and the average holding time is known
Erlang C A traffic model commonly used for provisioning data circuits
ERMES European Radio Messaging System. An ETSI paging system established in the 1990s. All European countries are supposed to provide spectrum for it.
ERP Effective Radiated Power
ERROR RESULT Message sent to unsuccessfully end TCAP transaction
ES Emergency Service(s), such as 911
ESA Enhanced Subscriber Authentication. A long term replacement to the TIA CAVE algorithm
ESC Emergency Services Call
ESF Extended Superframe Format. DS1 format that is used for most T1 links
ESIF ATIS Emergency Services Interconnect Forum
ESME(1) Emergency Services Message Entity. Entity that receives E911 messages from an MSC (e.g. ALI or S/R)
ESME(2) External SME. Used by SMPP to exchange short messages between incompatible technologies
ESMR Enhanced SMR. Allows ‘cellular’ service as well as traditional SMR services
ESN(1) Electronic Serial Number. 32 bit identifier of an AMPS, CDMA or TDMA mobile. May eventually be replaced by MEID.
ESN(2) Emergency Service Number
ESNE Emergency Services Network Entity. Entity that is connected to an E911 trunk from an MSC (e.g. S/R or PSAP)
ESP(1) Emergency Service Provider
ESP(2) Enhanced Subscriber Privacy. Stronger TIA voice encryption algorithms than those originally provided with CAVE
ESP(3) IETF Encapsulating Security Payload, RFC 2406
ESRD Emergency Service Routing Digits. An NANP number that routes a call to a PSAP and identifies the cellsite or sector that the call originated from
ESRK Emergency Service Routing Key. A temporary phone number that routes an emergency call to the correct PSAP and allows access to information in the ALI
ESZ Emergency Services Zone. A geographical region served by a single emergency call answering service.
Ethernet A LAN protocol using collision detection to resolve access contention (CSMA/CD). Available in 10Mbps, 100Mbps and 1Gbps variants. Standardized as IEEE 802.3.
ETR ETSI Technical Report
ETS European Telecommunication Standard
ETSI European Telecommunications Standards Institute
EUI-48(1) 48 bit IEEE MAC Address. Replaced by EUI-64.
EUI-64(2) 64 bit IEEE MAC Address. Replaces EUI-48.
EUIMID Expanded UIMID. A larger identifier for a cdma2000 UIM. There are two variants, the “Short Form” (SF_EUIMID) which is based on MEID and the “Long Form” (LF_EUIMID) based on ICCIDESN(1) a pUIMID is calculated.
EV-DO(1) See EvDO
EvDO 1x cdma2000 Evolution for High Speed Data Only. See HRPD and EVDV. A high speed CDMA data system. It does not support voice, except as VoIP. Revision 0 promised 2.4 Mbps download, 153 kbps upload on a 1.25 MHz carrier. Revision A was 3.1 Mbps down, 1.8 up. Revision B was 14.7 Mbps download and 4.9 Mbps upload in a 5 MHz carrier and Revision C promises 100 Mbps download and 50 Mbps upload in a 20 MHz carrier. See LTE and ADRC
EVDV CDMA 1x Evolution - Voice and High Speed Data services. Although it is more flexible, it is so far less popular than EvDO
EVM Error Vector Magnitude. The difference between the received coordinates of a symbol (defined by phase and amplitude) and the intended position (e.g. what was transmitted). This is a measure of error in digital modulation systems such as QAM.
EVRC Enhanced Variable Rate Voice Coder. An IS-95 voice coder for use on CDMA systems
EWC Enhanced Wireless Consortium. An association to promote the development of the IEEE 802.11n WLAN protocol
EWG GSMA Environmental Working Group


F-BCCH Fast Broadcast Control Channel
F-SCH Forward SCH (from BS)
f1 AKA message authentication function used to compute MAC
f2 AKA Message authentication function used to compute RES and XRES
f3 AKA Key generating function used to compute CK. Compare with f8.
f4 AKA Key generating function used to compute IK. Compare with f9
f5 AKA Key generating function used to compute AK. It may simply generate 0 if concealment of SQN is not required.
f8 AKA Ciphering Function. May be Kasumi. Uses CK, which is derived from RAND using f3
f9 AKA Integrity Protection Function. May be Kasumi. Compare with f4
FA Foreign Agent
FAC(1) FA Challenge
FAC(2) Final Assembly Code. The 2 digit IMEI ME manufacturer identity
FACCH Fast Associated Control Channel
FAQ Frequently Asked Questions
Fast Fading Fade duration short relative to channel frame length
FBI US Federal Bureau of Investigation
FC Feature Code. An asterisk followed by digits indicating the invocation of a feature (e.g. *73 may be used to disable call forwarding). Feature codes should be sent to the HLR for interpretation. There is no standardization of feature codes
FCC US Federal Communications Commission
FCCH GSM Frequency Correction Channel; downlink only, correction of MS frequencies, transmission of frequency standard to MS etc.
FCI Forward Call Indicator. Used to indicate whether a number portability query has occurred for this call (to prevent looping)
FCS Frame Check Sequence. A checksum for a transmitted frame
FDD Frequency Division Duplex
FDDI Fiber Distributed Data Interface
FDM Frequency Division Multiplex. See FDMA
FDMA Frequency Division Multiple Access. Compare with TDMA and CDMA
FDN Fixed Dialing Number
FDTC Forward DTC
FE Functional Entity. A logical element of a network. Not necessarily realized as a physically distinct device
FE-NTS Feature Enhanced NTS
FEC(1) Forward Error Correction
FEC(2) Forwarding Equivalence Class. An identity for packets that all get routed via MPLS in the same way
FER Frame Error Rate. The number of frames in error divided by the total. These frames are usually discarded, in which case this can be called the Frame Erasure Rate
FEXT Far End CrossTalk
FF GSMA Fraud Forum
FFPC CDMA Fast Forward Power Control
ffs For Further Study
FFT Fast Fourier Transform
FHMA Frequency Hopping Multiple Access
FHSS Frequency Hopping Spread Spectrum.
FIB Forward Indicator Bit. Indicates the start of a retransmission cycle in MTP. See BIB
FIFO First in, first out. A queuing methodology similar to lining up for a bank teller. Compare with LIFO
FIPS US Federal Information Processing Standards
FISU Fill-In Signal Unit. The keep-alive message for SS7 MTP
FLEX A Motorola one-way paging protocol that runs at 1600, 3200 or 6400 bps. Compare with POCSAG
FM(1) Frequency Modulation
FM(2) Follow-Me
FOCC Forward Control Channel. Used to send signaling messages from a base station to one or multiple mobiles
Foreign Agent IP node that receives packets from a Home Agent for delivery to a Mobile Node currently in its service area
FPLMTS Future Public Land Mobile Telecommunications Systems. Now IMT-2000
FQDN Fully Qualified DN. A domain name with enough information (including server name, if necessary, to determine a unique IP address). For example, if '' had two servers, 'alpha' and 'beta', '' would be fully-qualified, but '' would not.
FR Full Rate (e.g. for a voice coder). Compare with HR
FRAD FR Access Device
FSK Frequency Shift Keying
FSN(1) Forward Sequence Number. The sequence number of an MTP frame being transmitted. Contrast with BSN
FSN(2) Frame Sequence Number
FTAM File Transfer, Access and Management
FTI Fractional T1. A customer may lease a portion of a full T1
FTN(1) Forward-To Number
FTP Internet File Transfer Protocol
FTTC Fiber to the curb
FTTH Fiber to the home
FVC Forward analog voice channel, transmitted by an MS
FWA Fixed Wireless Access. See WLL
FWI Flash with Information; used to transmit data from an MS during a call


G.711 The ITU-T standard for PCM encoding telephone audio on an 64 kbps channel. Because it operates at an 8 kHz sampling rate (8 bits per sample) it can only encode frequencies between 0 and 4 kHz. There are two encoding variants. mu-law and A-law. A-law is used for international circuits and represents smaller signals with greater fidelity.
G3FAX Group III Facsimile service
G95 A sub-group of GGRF investigating roaming between GSM and CDMA systems based on TIA/EIA-95 and cdma2000
GAD Geographic Area Description. GSM 101.109 and 3GPP 23.032 defines this. Related to CGL in ATIS T1.628
GAIT GSM/TIA/EIA-41 Interoperability Trial
GALILEO A European positioning system based on 30 satellites and ground stations. Devices can position themselves based on accurate (atomic clock) time transmitted from the satellites and their knowledge of the satellite's positions. Similar to the US GPS
GAP SS7 ISUP Generic Address Parameter. Used in number portability to carry the LRN
Gateway MSC An MSC designed to receive wireless calls from the PSTN
Gaussian Noise Noise with constant power spectral density across the radio channel.
GBA Generic Bootstrapping Architecture. Uses key material located in an HLR, HSS or AAA to ‘bootstrap’ a key for other purposes, e.g. mobile application security A security association is established by the BSF with both the UE and NAF allowing secure communication between the UE and the NAF, without the NAF having any root key material.
Gbps Giga-bps. A data speed of billions of bits per second. See Mbps and kbps
GCC Group Call Control
GCCS Generic Call Control service for Parlay/OSA
GCF GSM Global Certification Forum
GCR Group Call Register
GDP ISUP Generic Digits Parameter
GECO Global Emergency Call Origination. Allows a phone to make an emergency call in an area where the emergency digits are different than at home.
GEO Geostationary Orbit (for a satellite)
GETS US Government Emergency Telecommunications Service
GFSK Gaussian FSK
GGRF GSM Global Roaming Forum within the GSM Association. Composed of GAIT, G95 and groups considering interworking with iDEN and TETRA
GGSN Gateway GSN. Connects to other packet data networks (e.g. internet). See SGSN
GHA Global Hexadecimal Address. See MEID.
GHOST GSM Hosted Short Message Teleservice. Allows TIA/EIA-136 messages to be delivered to a GSM MS
GHRC(1) CDG Global Handset Requirements for cdma2000
GHz One thousand million Hz. A measure of radio frequency
GIF Graphics Interface Format. A common graphics format suitable for computer-drawn graphics with few colors (up to 256). It supports simple animation. JPEG, PNG or TIFF are more suitable for photographs.
Giga Prefix to indicate one billion (e.g. Giga-bit). Abbreviated G. See Gbps
GII Global Information Infrastructure
GIS Geographic Information System. A system that combines mapping information with domain-specific information that can be queried by computers.
GIWU GSM Inter-Working Unit. An interface to various networks for data communications
Global challenge Method of authentication using the same random number (RAND) for every mobile in a cellsite or sector
GLONASS(1) Russian satellite-based location system. Compatible with GPS
GMM GPRS Mobility Management Protocol
GMSK Gaussian MSK
GMT Greenwich Mean Time. The reference point for time zones around the world.
GNSS Global Navigation Satellite System. A generic name for a satellite based positioning system. Currently, only GPS and GLONASS qualify but in future, other systems such as GALILEO and Beidou may be added.
Go Interface between the GGSN and PDF that allows the application of policy (network rules) to bearer usage.
goodput See throughput and badput
GPRS General Packet Radio Service. A GSM-based packet data protocol using up to all 8 of the time slots in a GSM channel. It supports data rates up to 115 kbps, although 10-40 kbps is more likely in practice. Most terminals do not support usage of more than 1-3 timeslots. The difference with HSCSD is that the bandwidth can be shared amongst many users, making it more flexible, but also more susceptible to speed degradation due to overloading. See ADRC
GPS Global Positioning System. A system for determining location based on comparing signals from several US military satellites. Compare with AOA, TOA
GR Telecordia Generic Requirements document
GRE Generic Routing Encapsulation. See RFC 1701
GRI GPRS Roaming Exchange. Provides interconnection, routing, DNS, security and QoS functions
GSL Global Service Logic
GSM Global System for Mobile Communications
GSM-R A GSM-based PAMR system developed by European railways.
GSMA GSM Association
GSN GPRS support node. See SGSN, GGSN.
GSTN General Switched Telephone Network. Synonym for PSTN
GT Global Title. A non-native SS7 address based on E.164 DNs, E.212 IMSI, etc.
GTA GT Address
GTAI SS7 SCCP GT Address Indicator
GTP GPRS Tunneling Protocol
GTT(1) Global Title Translation. A method of routing in SS7 networks based on an GTs and not Point Code
GTT(2) Global Text Telephony
GUG GVNS User Group
GUI Graphical User Interface
GUID(1) Synonym for UUID.
GUP Generic User Profile
GUTS General UDP Transport Service
GVNS Global Virtual Network Service
GW Gateway


H.245(1) A protocol used to control H.323 teleconferencing sessions.
H.248 ITU-T protocol to control the MGW
H.323 ITU-T recommendation for teleconferencing. See OpenH323
HA MIP Home Agent
HAC HA Challenge
HANDMREQ TIA/EIA-41 HandoffMeasurementRequest INVOKE message. Being replaced by HANDMREQ2
HANDMREQ2 TIA/EIA-41 HandoffMeasurementRequest2 INVOKE message. Used by the Serving MSC to determine the signal strength being received by a neighboring Candidate MSC. Replaces HANDMREQ2
Handoff The process of a MS changing from one frequency in one cell or sector to a different frequency in a neighboring cell or sector
HC Home Country
HCM Handset Configuration Management. See IOTA
HDB3 High Density Bipoloar Order 3 Encoding
HDLC High Level Data Link Control
HDML Handheld Markup Language
HDR High Data Rate. High speed data-only version of CDMA, standardized as EvDO. Now called HRPD
HDSL High bit rate DSL. Symmetric DSL used for corporate networking
HE Home Environment
Hertz A unit of frequency. See MHz, GHz, kHz
HF Hyperframe
HFC(1) HF Counter
HFC(2) Hybrid Fiber-Coax
HG Header Generator
HI Handover Interface
HINFO Host Information
HIPPI High-Performance Parallel Interface
HLPI Higher Layer Protocol Identifier
HLR Home Location Register
HNI Home Network Identifier. The MCC and MNC prefix of a group of IMSI codes.
Home Address An IP address permanently assigned to a device that is supported by Mobile IP. Messages routed to this address will arrive at the HA.
Home Agent IP node that receives packets at a Mobile Nodes static address and forwards them to a Foreign Agent for delivery at its current (‘care-of’) address
Home MSC The MSC to which the PSTN routes based on an MDN
HomeRF Promoters of the SWAP protocol for in-home wireless networking. This protocol was abandoned in 2003.
HPC High Probability of Completion
HR Half Rate (e.g. for a voice coder). Compare with FR
HRFWG HomeRF WG. Note that this protocol was abandoned in 2003
HRL Header Reduction Lower
HRPD cdma2000 High Rate Packet Data (formerly EvDO and HDR). It combines TDM on the forward link to provide from 38kbps to 2.5Mbps data rates. The reverse link supports speeds from 9.6kbps to 154kbps
HRU Header Reduction Upper
HS-DSCH HSDPA DSCH. A high speed channel for transmitting data to a W-CDMA mobile.
HS-PDSCCH HSDPA DL control channel
HS-PDSCH HSDPA DL physical channel
HSCSD High Speed Circuit Switched Data. GSM enhanced to allow the concurrent use of up to four timeslots, providing a theoretical maximum 57.6 kbps data rates, although maximum rates of 28.8kbps to 43.2kbps are more realistic in practice. The main difference with GPRS is that the timeslots are assigned exclusively to one mobile for the duration of a data call.
HSDPA 3GPP High Speed Downlink Packet Access. Provides higher data rates ‘down’ from the network to the mobile at about 1.5 Mbps in a 5 MHz carrier. Uplink speeds will be the same as EDGE – 384 kbps. See HSUPA and HSPA Evolution. See ADRC
HSG Header Stripping and Generation
HSGW(1) HRPD Serving Gateway. Provides converged mobility management between eHRPD and LTE networks.
HSPA Evolution An evolution of HSDPA and HSUPA that is promising downlink speeds of 28 Mbps, uplink speeds of 11.5 Mbps in a 5 MHz carrier. See ADRC
HSS 3GPP Home Subscriber Server. Similar to AAA
HSSI High Speed Serial Interface. A serial interface that can be used for very short distances (up to 50 feet), supporting speeds up to 52 Mbps
HSUPA 3GPP High Speed Uplink Packet Access. Complements HSDPA by providing higher throughput on the W-CDMA link for uploading (MS to network). Rates for initial systems will be about 1 Mbps but eventually 5.76 Mbps is promised. The RTT is estimated as under 50 ms. See HSPA Evolution and ADRC
HTML Hypertext Markup Language
HTTP Hypertext Transfer Protocol . See RFC 2068
https Secure HTTP
Hyperband Handoff Handoff between two different frequency bands (e.g. 800 MHz cellular and 1800 MHz PCS)
Hz Cycles per second. A measure of radio frequency


I-CSCF Interrogating CSCF. Main contact point for IMS connections to a carrier's subscribers
I-SCM Interrogating SCM
I-WLAN WLAN Interworking with a 3GPP cellular network.
IA5 International Alphabet 5. Basically the ASCII character set
IAM SS7 ISUP Initial Address Message. Used to initiate a call
IANA Internet Assigned Number Authority. Mostly superseded by ICANN
IAP Intercept Access Point. A point within the telecommunications network that provides voice or data for CALEA interception to a DF
IAPP Inter-Access Point Protocol. An IEEE protocol to allow the secure transfer of MS context from one AP to another. It is based on IEEE 802.11f.
IBC Iterated Block Ciphers
IC(1) see IXC
IC(2) Integrated Circuit
ICANN The Internet Corporation for Assignment Names and Numbers. Performs top level resource assignment tasks for the internet, e.g. for domain names and IP addresses.
ICCID An identifier for a SIM or UIMLuhn checksum. The number always starts with the digits ‘89’ (indicating a ‘Telecommunications’ card) followed by a 1-3 digit E.164 Country Code and 1-4 digit Issuer Identification Number. These first digits, which cannot number more than 7, are followed by the Individual Account Identification Number which is most likely to be 11 digits long. Administered according to ITU-T Recommendation E.118
ICE(1) Interactive Connectivity Establishment. A Methodology for NAT Traversal for SIP.
ICMP Internet Control Message Protocol. Method for reporting errors and performing loopback testing on the internet
ICO Intermediate Circular Orbit
ICS Implementation Conformance Statement
IDB ITS Data Bus (SAE J2366)
iDEN Integrated Digital Enhanced Network. Motorola’s proprietary system for E-SMR, used by Nextel and others. Based on GSM
IDL Interface Description Language
IDSL ISDN Digital Subscriber Line. Just a fancy name for ISDN
IE Information Element
IEC(1) See IXC
IEC(2) Internet Engineering Consortium
IEC(3) International ElectrotechnIcal Commission and the identity of standards produced by this organization.
IEEE Institute of Electrical and Electronic Engineers
IEEE 802.15.1 The IEEE Standard for Bluetooth
IEEE 802.15.4 The IEEEStandard for ZigBee
IEEE-ISTO IEEE Industry Standards and Technology Organization
IESG Internet Engineering Steering Group. Group that oversees the activities of IETF
IETF Internet Engineering Task Force. Standards setting body for the Internet
IF Information Flow
IFAST International Forum on AMPS Standards Technology. Allocates IRM and SID codes
IFFT Inverse FFT
IGP Interior Gateway Protocol. See MPLS
IGS(1) International GNSS Services. A voluntary federation of more than 200 worldwide agencies that pool resources and permanent GPS and GLONASS station data to generate higher precision data and products. It is likely that the new GNSS, GALILEO, will be included in the future.
IIF Interworking and Interoperability Function
IK Integrity Key. Protects (via encryption) the contents of signaling messages. In AKA it is derived from RAND using f4. It is applied to messages using f9
IKE Internet Key Exchange Protocol
ILEC Incumbent LEC. The former monopoly local telephone carrier. cf CLEC
ILM Incoming Label Map. See MPLS
IM(1) IP Multimedia. A network using IP to transport voice, signaling, text, video etc.
IM(2) Instant Messaging
IM-MGW IM Media Gateway Function
IMAP4 Internet Message Access Protocol. IETF RFC 2060
IMC Internet Mail Consortium
IMD Inter-Modulation Distortion. The interaction of two or more signals, producing an unwanted additional signal
IMEI 56 bit GSM International Mobile Equipment Identity. Composed of TAC + FAC + SNR + spare digit. A check digit is also included, but not always transmitted. See also IMEISV and MEID
IMEISV IMEI with Software Version Number. Composed of TAC + FAC + SNR + SVN
IMGI Inernational Mobile Group Identity
iMode Japanese (NTT DoCoMo) wireless internet access system. See cHTML
IMRN IP Multimedia Routing Number
IMS IP Multimedia Subsystem. An All-IP wireless system, where data, voice and signaling are all carried as IP packets.
IMSI International Mobile Subscriber Identity. Formerly called International Mobile Station Identity. Based on the ITU-T E.212 numbering plan. Composed of MCC MNC and MSIN. The only subscription identifier used by GSM and the future subscription identifier for CDMA.
IMSI_M cdma2000 MIN-based IMSI.
IMSI_O Operational value of IMSI used by a cdma2000 MS. Either IMSI_M or IMSI_T
IMSI_O_S The last 10 digits of IMSI_O. Used for compatibility with older CDMA systems that relied on the 10 digit MIN.
IMSI_T True IMSI used by cdma2000. Compare with IMSI_M. See IMSI_O
IMT-2000 International Mobile Telecommunications for the year 2000 (or thereabouts)
IMTS-2000 The ITU 3G initiative. It does not define specific protocols, but just the performance goals for them, such as bandwidth. Specifications are being developed by 3GPP and 3GPP2.
IMUI International Mobile User Identity
IN Intelligent Network. Wireless equivalents are WIN and CAMEL
INAP IN AP. The IN messaging protocol
INC Industry Numbering Committee (for the NANP)
INI IRM Network Identifier. The first four digits that uniquely identifies a carrier HLR
INM Integrated Network Management
INN Internal Network Number
INS(1) Intertial Navigation System. A device that calculates position based on estimating its own movement relative to a starting position at a known location. Can be quite accurate in the short term, but gets continually less accurate until reset at a known location again.
Integrity Preventing information (e.g. a data transmission) from being manipulated. This can be accomplished by putting a MAC on each message.
Interface A connection between two network elements. Compare with Protocol
Interleaving Mixing of bits upon transmission according to a simple pattern (e.g. organizing bits in a matrix by columns and transmitting by rows) to somewhat randomize the output and protect from burst of noise on the RF channel
Intermodulation Interference RF interference within a channel generated as one or more intermodulation products within the receiver itself, typically as the result of the presence of very strong signals in adjacent bands. Contrast with Systemic Interference and Non-systemic Interference
Intserv Integrated Services
INVOKE Message sent to initiate an TCAP transaction
IOS Inter-Operability Standard. A version of the TIA/EIA-634 A-interface that enhances inter-vendor compatibility
IOT Inter-Operator Tariff
IOTA IP-based Over-the-Air configuration management
IP(1) Intelligent Peripheral
IP(2) Internet Protocol
IP-M IP Multicast
IPCP PPP IP Control Protocol
IPDR Internet Protocol Detail Record. An internet oriented record for carrying charging details for services. Compare with CIBER, BAF, TAP, EMI
IPHC IP Header Compression. Provides compression (and decompression) of TCP, UDP and IP headers.
IPLMN Interrogating PLMN
IPoA IP over ATM
IPR Intellectual Property Rights (e.g. patents). See DRM.
IPSEC IP Security. Compare with SSL (for TCP). See IETF RFC 2401. Also spelled IPSec
IPv4 IP Protocol Version 4. The version currently in use in the internet, using 32 bit addressing. See also IPv6.
IPv6 IP Protocol Version 6. The version that is supposed to provide significantly larger and more powerful addressing, and eventually replace IPv4. Don’t hold your breath
IPv6CP IPv6 Control Protocol
IR(1) Intelligent Roaming
IR(2) Infra-Red
IR(3) Initialization and Refresh Packet. RFC 3095
IRA International Reference Alphabet
IRDB IR Database. A database that can be loaded into a phone over the radio interface that prioritizes systems that may be detected by a phone based on carrier agreements
IREG GSMA International Roaming Experts Group.
IRG IFAST International Roaming Guide
IRI Intercept (i.e. LAES) Related Information
IRM International Roaming MIN. A mobile subscription identifier beginning with the digit 0 or 1 to avoid conflict with NANP MINs
IRP Integration Reference Point
IRS Internet Reachability Service
IS TIA Interim Standard
IS-124 Wireless call detail and billing record format for online transfer
IS-136 Second generation TDMA air interface standard
IS-2000 cdma2000 air interface standard. A successor to TIA/EIA-95-B
IS-41 Wireless intersystems operation standard. Now called TIA/EIA-41
IS-41-C IS-41 Revision C (Intersystem Operations Standard)
IS-54 First generation TDMA Radio Interface standard
IS-634 See TIA/EIA-634
IS-637 CDMA short message service standard
IS-683 see TIA/EIA-683
IS-756 A TIA standard for WNP
IS-801 TIA/EIA interim standard for CDMA MS-assisted position determination
IS-91 Most advanced analog air interface standard (including NAMPS)
IS-93 Wireless-PSTN interface standard
IS-95 cdmaOne CDMA air interface standard
ISAKMP Internet Security Association and Key Management Protocol
ISC International Switching Centre
ISDN Integrated Services Digital Network. PSTN utilizing SS7 interfaces
ISI Inter-Symbol Interference
ISIS Intermediate System - Intermediate System IP routing algorithm.
ISM Industrial, Scientific, Medical frequency band (2.45-2.5 GHz). Available around the world for unlicensed applications, generally using low power and short distances
ISMA Interference Sense Multiple Access
ISO International Organization for Standardization
ISO-8859-1 The most common 8-bit character set used for web pages. An ISO/IECstandard. Also see UNICODE
isotropic Radiating equally in all three dimensions (as opposed to directional, with energy being focussed more in some directions than other).
ISP Internet Service Provider
ISUP ISDN User Part. SS7 signaling between switches. Standardized in ANSI T1.113 and ITU-T Q.760-769
ITAR US International Traffic in Arms Regulations. These rules used to govern export of encryption technology in the US and, to some extent, in Canada. Replaced by EAR
ITN Individual Telephone Number Pooling. Phone numbers can be assigned to carriers one at a time, instead of in blocks of 1,000 or 10,000
ITOT(1) ISO Transport Service on top of TCP. Emulates the services of ISO protocols such as COTP but with TCP as the actual transport protocol. See RFC 2126.
ITS(1) Intelligent Transportation System (“Smart Highways”)
ITS(2) IP Transport Subsystem
ITU International Telecommunications Union
ITU-R ITU - Radio Communications Division
ITU-T ITU - Telecommunications Division
Iu Interface between an RNC and CN (MSC, SGSN or CBC). Support for this within GSM has been suggested, but is unlikely. See also Iub, Iur.
IUA ISDN Q.921 User Adaptation Layer
Iub A 3GPP interface between an RNC and a Node B. See Iu, Iur.
Iur A 3GPP interface between two RNCs. This is a logical interface, and the RNCs may not be connected by point-to-point physical links. See Iu, Iub.
IV Initialization Vector. A 24-bit session-specific key for WEP
IVR Interactive Voice Response
IWF Inter-working Function. Used for wireless data interworking between digital mode data and analog (e.g. modems)
IXC Inter-eXchange Carrier. A carrier licensed to provide long distance services


J-STD- Joint ATIS-T1/TIA standard
J-STD-025 LAES standard jointly produced by ATIS T1 and TIA TR-45
J-STD-034 Wireless E911 Phase I standard (cellsite and mobile identification, callback capabilities). See J-STD-036
J-STD-036 Wireless E911 Phase II standard (position of caller within 125m/400ft). See J-STD-034
J2EE Java 2 Enterprise Edition
J2ME Java 2 Micro Edition
JAIN Java APIs for Intelligent Networks
Java A C-like programming language that is compiled into a virtual machine language providing efficiency close to that of languages compiled into native machine code while providing portability of the compiled program. Each computer system that wants to run Java has to provide a virtual machine
JCP Java Community Process
JDC Japanese Digital Cellular
JFIF JPEG File Interchange Format
JIP ISUP Jurisdiction Information Parameter
JPEG Joint Photographic Experts Group. Not usually used to refer to the group, but a graphics format created for them that is suitable for digital photographs and similar images. It supports 24 bit color as well as variable levels of compression and quality. It should be referred to as JFIF, but isn't. cf GIF, PNG, TIFF
JSR Java Specification Request
JSR 177 JSR for Security and Trust services API for J2ME
JTC Joint Technical Committee (e.g. with members of more than one SDO)


Kasumi A block cipher used by AKA for the A5/3, f8 and f9 algorithms. See the wikipedia entry for more details
kbps kilo-bps. A data speed of billions of bits per second. See Mbps and Gbps
Kc GSM cipher key. Used for voice encryption
KDF Key Derivation Function
KG Key Generator
kHz kilo-Hertz. Thousands of cycles per second. See MHz and GHz
Ki GSM subscriber authentication key
kilo Prefix to indicate one thousand (e.g. kilo-bit). Abbreviated k. See kbps
KSG Keystream Generators
KSI Key Set Identifier
KSS Key Stream Segment


L1(1) Layer 1
L1(2) A GPS transmission frequency at 1575 MHz
L2 Layer 2
L2TP L2 Tunnel Protocol. Defined in RFC 2661. Successor to PPTP. IP packets are wrapped in a layer containing another set of IP addresses and possibly also control messages. The detailed format varies depending on whether the transport protocol is IP, UDP or another PSN type.
L3 Layer 3
LAC(1) Link Access Control
LAC(2) Location Area Code. 16 bit number identifiying a location area (i.e. group of base stations) within a GSM PLMN
LAES Lawfully Authorized Electronic Surveillance. See CALEA, J-STD-025, surveillance
LAI GSM Location Area Identity. Composed of MCC + MNC + LAC
LAK Local Authentication Key
LAN Local Area Network. Compare with WAN, MAN.
LAP Link Access Protocol
LAPB Link Access Protocol, Balanced
LAPD Link Access Protocol for the ISDN D Channel
LATA Local Access and Transport Area. US local telephone service area
LB Letter Ballot
LBA Location Based Application
LBC Last Batch Count. Exchanged by CIBER billing clearinghouses to ensure they do not get out of sequence with each other.
LBS Location Based Services
LCP Link Control Protocol. A subset of PPP that is used to negotiate and establish link capabilities, including authentication
LCS Location Services. This usually implies positioning of an MS for commercial services, not emergency services
LCSM LCS Manager
LDAP Lightweight Directory Access Protocol. See IETF RFC 3377. Compare with X.500 DAP
LDP Label Distribution Protocol. See MPLS
LDT Location Determination Technology
LEA Law Enforcement Agency
Leakage Inability to bill for a service
LEAP Lighweight EAP. A Cisco proprietary version.
LEC Local Exchange Carrier (wireline carrier for local calls). Also see ILEC and CLEC
LEMF Law Enforcement Monitoring Facility (for LAES)
LEO Low Earth Orbit
LER Label Edge Router. See MPLS
LERG Local Exchange Routing Guide. Includes a list of valid number blocks in the NANP
LFB Lookahead For Busy
LIDB Line Information DataBase. Used for validating collect calls, 3rd party calls, etc.
LIF Location Interoperability Forum within OMA
LIFO Last in, first out. A queuing methodology similar to stacking dishes and using the dish on the top of the stack. Compare with FIFO
LIR Location Identification Restriction. Prevents the location of a mobile phone from being revealed (with legal exceptions for E911, etc.)
LLA-RHOC Link Layer Assisted ROHC
LMDS Local Multipoint Distribution Service. Uses the 27.5-31.3 GHz frequency band to serve mulitple points within a radius of 3-5km. Most carriers in this space have abandoned it or gone bankrupt. See MMDS.
LMM Localized Mobility Management to improve local handover performance in Mobile IP
LMR Land Mobile Radio
LMSD Legacy MS Domain. Refers to existing SS7-based telecommunications systems, when accessed from an All-IP system. See MMD
LMSI Local Mobile Station Identity. See TMSI
LMU GSM Location Measurement Unit
LND Last Number Dialed
LNP Local Number Portability. Allows consumers to keep a phone number (MDN) when changing carriers within the same geographical region
LNPWG Local Number Portability Working Group of NANC
LORAN(1) Long Range Aid to Navigation. A land based navigation system based on the difference in time between signals received from several transmitters at known locations.
LOS Line of Sight. A direct path through the air from transmitter to receiver. Always desirable for wireless communications, although not always necessary (e.g. for cellular/PCS)
LPC Linear Predictive Coding
LPDU Link Protocol Data Unit. A frame
LRF Location Registration Function. See WIN
LRN Location Routing Number. A routing number that identifies the terminating switch for a Ported DN
LSB Least Significant Bit or Byte. Compare with MSB
LSMS Local Service Management System. Telephone carrier interface that downloads information from the NPAC into one or more NPDBs
LSP Label Switched Path. See MPLS
LSPI Proposed SS7 ISUP Local Service Provider Identification
LSR Label Switching Router. See MPLS
LSSU Link Status Signal Unit. The link status message for SS7 MTP
LT Line Termination
LTE A GSM competitor to EvDO Revision C promising similar 4G data rates. See ADRC, E-UTRA and eUTRAN. Initial systems showed real rates on a presumably lightly loaded system of 12 Mbps downstream and 5 Mbps upstream. In February, 2011, Andrew Seybold found average download speeds of about 15 Mbps and upload of about 4 Mbps in a Verizon system using 10 MHz in each direction.
LUDT Long UDT. Supports messages up to 3 kilobytes in length


M2M Machine To Machine. Communications between unattended machines. Most electronic communications is between machines but in many cases, such as a cellphone or PC, this is usually only because a person is using the device. An example of an M2M scenario is when a heat or alarm sensor communicates with a central computer, perhaps with the central computer providing feedback to other devices to shut off a malfunctioning machine, turn on fans or other automated control
M2PA SS7 MTP2 Peer-to-Peer User Adaptation Layer
M2UA SS7 MTP2 User Adaptation Layer
M3UA SS7 MTP3 User Adaptation Layer. Resides above SCTP and below SCCP in an IP telecom signaling protocol stack.
MAAL Management ATM Adaptation Layer. Maps management requests from system management to SAAL. See ATIS T1.652
MABEL Major Account Billing Exchange Logistical Record. Defined by Cibernet to facilitate centralized billing for large account customers
MAC(1) Medium Access Control
MAC(2) Message Authentication Code. In AKA, a value derived from SQN, RAND and AMF using f1 that shows that the sender was in possession of certain secret information (i.e. is authentic).
MAC Address(1) MAC Address. Originally 48 bit EUI-48 but now expanded to the 64-bit EUI-64. Uniquely identifies a device that will be accessing the internet through any interface such as Ethernet, WiFi or cellular.
MACA Mobile Assisted Channel Allocation. Mobile determines the best alternate cellsite to originate a call in, when no channels are available in the current site
MAH Mobile Access Hunting. Termination to one of a group of mobiles
MAHO Mobile Assisted Handoff. Mobile measures signal strength at neighoring base stations to determine which to handoff to
MAN Metropolitan Area Network. Compare with LAN, WAN
MANET Mobile ad hoc Network. A collection of wireless nodes that can dynamically form a network without any fixed network infrastructure.
MAP Mobile AP. Protocol that interconnects wireless telephone systems. See GSM and TIA/EIA-41
MBI MIN Block Identifier. The first 6 digits (usually) of a North American MIN, when assigned separately from the MDN. The first digit is always 2-9 (inclusive). Digits 0 and 1 are reserved for IRM codes.
MBMS UTRA Multimedia Broadcast and Multimedia Service
Mbps Mega-bps. A data speed of millions of bits per second. See Gbps and kbps
MC(1) Short Message Center
MC(2) Multi-carrier
MCC E.212 Mobile Country Code. First 3 digits of IMSI
MCFTP Multi-Channel Flow Treatment Protocol
MCI Malicious Call Identification
MCL Minimum Coupling Loss. The minimum loss required between a transmitter and a nearby receiver to avoid adversely affecting receiver performance.
Mcps Million Chips-per-second. See CDMA and W-CDMA
MCSE Microsoft Certified Systems Engineer
MD-IS Mobile Data - Intermediate System. A CDPD term
MD5 Message Digest 5. A secure hashing algorithm. See SHA-1
MDN Mobile DN
MDS Multi-Point Distribution System.
ME Mobile Equipment. Synonym for UE. Contrast with MS
MEA Message Encryption Algorithm
Mega Prefix to indicate one million (e.g. Mega-bit). Abbreviated M. See Mbps
MEGACO Media Gateway Control - IETF Working Group
MEI Mobility Event Indicator
MEID A 56 bit Mobile Equipment Identity for CDMA and TDMA MS. Similar to the GSM IMEI, but allowing hexadecimal digits, and with a simplified structure (2 digit region code, 6 digit manufacturer code, 6 digit serial number). ESN and MEID are assigned by the TIA in their role as GHA.
MEMS Micro-Eletronic Mechanical System
MESA Mobility for Emergency Service Applications. A joint ETSI/TIA project to increase the interoperability of emergency service communications.
mesh A form of networking where access to a server can be accomplished by routing through other clients that are physically closer
meta-language A language that can be used to define other languages. See ASN.1 and BNF
MExE 3GPP TSG-T Mobile Execution Environment
MF(1) Multi-frequency tone signaling. Used for trunk signaling
MF(2) UIM Master File. Compare with EF and DF
MG Media Gateway
MGC MG Controller
MGCF MG Control Function
MGCP MG Control Protocol. A VoIP call control standard. Also see older protocol SGCP
MGW Media Gateway. Interface between packet environment of the CN and circuit environment of PSTN
MHz Million Hz. A measure of radio frequency
MIB Management Information (Data)Bases
MIH Media Independent Handover. An IEEE 802.11 term indicating handover between 802.11, 802.3 or 802.16 and another radio interface.
MIHF MIH Function. A cross-layer entity, defined by IEEE 802.21, that provides mobility support through SAPs offering Event, Information and Command services.
MIME Multipurpose Internet Mail Extensions
MIMO Multiple Input, Multiple Output antennas. This increases throughput and reduces bit error rates compared to traditional antenna systems which transmit and receive through a single antenna.
MIN Mobile Identification Number. 10 digit identifier of a mobile subscription. IRM for cdma2000, TDMA, AMPS. A MIN intended for use outside North America is usually an IRM assigned by IFAST
MIN1 The last 7 digits of a MIN encoded in a wierd, but compact, 24 bit binary format
MIN2 The first 3 digits of a MIN encoded in a very wierd, but compact, 10 bit binary format
minimization Removal of information that has been collected, but that is outside the scope of a court order. See LAES
MIP Mobile IP. IETF RFC 2002
MIPS Million Instructions per Second. Measurement of processor speed
MISP Mobile Internet Service Provider
MLC OMA/3GPP Mobile Location Center
MLP Mobile Location Protocol. An XML-based protocol developed by the OMA LIF group.
MLPP Multi-Level Precedence and Pre-emption
MLTS Multi-line Telephone System
MM(1) Mobility Management
MM(2) Multimedia Message
MM1 MMS interface between UA and MMS Relay/Server
MM2 MMS interface between MMS Relay and MMS Server
MM3 MMS interface between MMS Relay/Server and External Servers for fax, email etc.
MM4 MMS interface between two MMS Relay/Servers
MM5 MMS interface between MMS Relay/Server and HLR
MM6 MMS interface between MMS Relay/Server and user databases
MM7 MMS interface between MMS Relay/Server and VAS applications
MM8 MMS interface between MMS Relay/Server and billing systems
MMD Multi-Media Domain. An IP-based signaling system supporting voice, video, graphics, sound and application data, such as email in an integrated fashion. Contrast with LMSD. See IMS
MMDS Multi-channel Multi-Point Distribution Service. Uses the 2.1-2.7 GHz frequency band. The success of this technology has been about as poor as its cousin, LMDS.
MMI Man-Machine Interface
MML Man-Machine Language. A human-readable language devised for communications between a human and a computer. Examples of formal languages in telecommunications are ITU-T Z.300 and the related TL1. These languages are textual and most humans are unlikely to want to use them directly, so they are more likely to take the place of a human-readable (i.e. ASCII character) protocol, with a GUI for the human to view and control the interactions with the computer more effectively and pleasantly.
MMS MM Service (e.g. text, audio, graphics)
MMSE Multimedia Messaging Service Environment
MMSNA MMS Network Architecture
MMTA MultiMedia Telecommunications Association. A subsidiary of TIA
MN Mobile Node. An internet term for a mobile device capable of IP communications. See Mobile IP
MN-FA MN Foreign Authentication. An extension to MIP that provides stronger authentication. See IETF RFC 3012
MNC E.212 Mobile Network Code (identifies an individual carrier, or a portion of a carrier network). Part of IMSI
MNIC Mobile Network Identification Code
MNID MN Identification
MNO Mobile Network Operator. A carrier.
MNP Mobile Number Portability. See LNP, WNP
MO Mobile Originated/Originating
Mobile IP A set of protocols that allows a MN to roam on the internet. Not widely implemented.
Mobile Node An IP network node that has both a static address and a ‘care-of’ address associated with it. IP packets can be routed to it via a Home Agent (at its static address) and a Foreign Agent (at its care-of address)
Mobility The capability of a device to initiate or receive services in many different systems, and to maintain session while travelling between systems.
Mobitex An Ericsson Wireless Data protocol, once known as RAM Mobile Data in the US.
MOS Mean Opinion Score. A method of measuring quality (e.g. of wireless voice transmission) by asking people to rank their opinion on a numeric scale, and then averaging the results. Sophisticated, huh!
MoU(1) GSM Memorandum of Understanding. The guidelines under which GSM systems are implemented
MoU(2) Minutes of Use. A common measure of the usage of a group of subscribers
MPC Mobile Positioning Center. Interfaces between MSC, PDE, CRDB and ESME
MPC-MLQ(1) Multipulse LPC with Maximum Likelihood Quantization audio codec used in G.723.1. Operates at a bit rate of 6.3 kbps
MPCAP Mobility Positioning Capabilities
MPEG Motion Pictures Experts Group. Not usually used to refer to a group but a format for audio/video compression (and, obviously, decompression)
MPLS Multi Protocol Label Switching. An IP protocol (RFC 3031) designed to provide preferred treatment to priority traffic to achieve a higher QoS. Every packet labeled with the same FEC gets the same treatment
MPS Minimum Performance Standards/Specification.
MRF Media Resource Function. Provides conference bridges, announcements, tones and so forth to IP-based telephony networks. See MRFC and MRFP
MRFC MRF Controller
MRFP MRF Processor. Provides tones, recordings, conference bridges etc.
MRP Market Representation Partner. A participant in the 3GPP or 3GPP2 process that represents the marketing of technology in a region, such as 3G Americas for 3GPP or CDG for 3GPP2.
MS(1) Mobile Station (wireless phone)
ms(2) Milliseconds. Thousandths of a second. Also msec
MS-SME SME embedded in MS
MSA Metropolitan Statistical Area. CGSA for urban cellular systems. Also used for licensing the FCC AWS D band.
MSAG Master Street Address Guide. A database of street names and house number ranges that define ESZ and their associated ESNs to enable proper routing of 911 calls. See E911.
MSB Most Significant Bit or Byte. Compare with LSB
MSC Mobile Switching Centre
MSC-G See Gateway MSC
MSC-H See Home MSC
MSC-O See Originating MSC
MSC-S Serving MSC
MSC-V Visited MSC. The MSC which a mobile is currently registered in
MSCIN MSC Identification Number
msec Milliseconds. See ms
MSEIA MS Emergency Information Assistance
MSID Mobile Station Identifier. A MIN or an IMSI. See IMSI_O
MSIN Mobile Subscriber Identity Number. Unique number assigned to a subscriber as part of IMSI
MSISDN MS ISDN number. Same as MDN
MSK Minimum Shift Keying. FSK where peak-to-peak FM deviation is half the data rate
MSO CDMA Markov Service Option
MSP Multiple Subscriber Profile
MSRN Mobile Station Roaming Number. The GSM equivalent of the ANSI-41 TLDN
MSS(1) Mobile Satellite System/Service
MSS(3) Multimedia Streaming Service
MSU Message Signal Unit. The payload message for SS7 MTP
MT Mobile Terminated/Termination/Terminal. The UE is composed of the MT and SIM/USIM and possibly other peripherals
MTA(1) Major Trading Area
MTA(2) Mail Transfer Agent
MTE Months to Exhaust. The time at which a numbering resource (e.g. area code) is expected to be fully utilized
MTP Message Transfer Part (SS7 transport layer)
MTP2 MTP Layer 2
MTP3 MTP Layer 3
MTSO Older term for MSC
MTTR Mean Time to Restore (after failure)
MTU Message Transfer Unit
Multipath A radio link between the transmitter and receiver comprised of multiple paths which include intermediate reflections from various surfaces, usually due to non-line of sight communication paths
MUX Multiplexer
MVNE Mobile Virtual Network Enabler. Provides infrastructure and services such as billing, subscriber management and operations support to MVNOs.
MVNO Mobile Virtual Network Operator. A company that markets cellular service but contracts with facilities-based cellular carriers to actually provide the coverage
mW milli-Watt
MWIF Mobile WIreless Internet Forum. Promotes the use of a single All-IP network for future wireless systems (e.g. convergence of 3GPP and 3GPP2 protocols)
MWN Message Waiting Notification (e.g. stutter dial tone or an indication on a wireless phone's display)
MWNE Managed Wireless Network Entity. A piece of equipment that provides OA&M data
MX Mail Exchange (internet mail server)


N-1 Switch The switch responsible for LNP queries
NAA Network Access Application
NACK Negative ACK
NAF Network Application Function of GBA.
NAI Network Access Identifier. This is an email-like address format used to identify a AAA or a device with an interface to one.
NAM Number Assignment Module. A portion of a mobile phone that stores a single user profile, including MIN and IMSI, but not ESN
NAMPS Narrowband AMPS
NANC North American Numbering Council. The organization responsible for overseeing the distribution of telephone numbers in the NANP
NANP North American Numbering Plan
NANPA North American Numbering Plan Administrator (or Area)
NAPTR Number Authority Pointer. See IETF RFC 2915.
NAS(1) Network Access Servers
NAS(2) Non-Access Stratum. Protocols between the UE and the core network that are transparent to the RAN (e.g. SMS)
NAT Network Address Translation. Maps an internal set of IP addresses to an external set (perhaps assigned dynamically by DHCP)
NAT-PMP(1) NAT Port Mapping Protocol
NBAP Node B Application Part
NCAS Non-Call Associated Signaling. Compare with CAS
NCG Network Capability Gateway. Obsolete. See OSA-SCS
NCGW Synonym for NCG. Obsolete. See OSA-SCS
NCS National Communication System. Responsible for US Government communications, including WPS and GETS
NDC E.164 National Destination Code
NDS Network Domain Security
NE Network Entity
NEBS Network Equipment Building Systems
NEMA-0183(1) Electrical interface for communications between maritime electronic devices. This includes some GPS data.
Net Additions Increase in new revenue-generating subscribers over a time period (usually a quarter year)
NFCC Network Firewall Configuration and Control
NFS Number Field Sieve. Used in cryptography
NGN Next Generation Network. ITU-T term for future wireless systems with even higher speed data capabilities.
NHLFE Next Hop Label Forwarding Entry. See MPLS
NHP No-Header Packet. See RFC 3242
NI(1) Network Identity
NI(2) Number Incomplete
nibble Four bit
NID Network Identification. A number that uniquely identifies a portion of a wireless carrier’s total system. Used by TIA/EIA-95 (CDMA) systems
NIDS Network-Initiated Data Session
NIIF Network Interconnection Interoperability Forum
NIST US National Insitute of Standards and Technology
NL Neighbour List
NMR Network Measurement Results
NMSI National Mobile Subscription Identity. MNC + MSIN
NMT Nordic Mobile Telephone. An analog cellular system available either in the 450 MHz or 900 MHz bands
Node B Logical node in the 3GPP RNS responsible for radio transmission/reception in one or more cells to and from the UE. Terminates the Iub interface towards the RNC.
Non-repudiation Ensuring that a communication cannot be disavowed later
Non-systemic Interference RF interference within a channel used in a wireless system that emanates from a transmitter that is not part of the same system, and that may have undefined channel characteristics. This is of greatest concern for systems operating in unlicensed bands, such as ISM. Compare with Systemic Interference
nonce A number that is used only once. Often used in cryptography
NP Number Portability
NPA NANP Numbering Plan Area (i.e. area code)
NPAC NP Administration Center. Often used to refer to the NPAC SMS
NPDB Number Portability Database. A list of ported numbers and associated LRNs used for LNP routing
NPDE Network PDE
NPDU Network Protocol Data Unit. A packet
NPI Numbering Plan Identifier
NPM Non-Public Mode Service
NPRM FCC Notice of Proposed Rulemaking
NRM Network Reference Model (e.g. TIA/EIA/TSB-100)
NRN Network Routing Number
NRTL Nationally Recognized Test Lab
NS Authoritative Name Server for a Domain. Converts between a domain name (e.g. and an IP address and related information
NS/EP US National Security and Emergency Preparedness. See WPS
NSA US National Security Agency. Keeps a tight grip on exports of US encryption technology
NSDPB&S Non-signaling Data Protocol for Billing and Settlement. subset of IS-124
NSDPF Non-signaling Data Protocol for Fraud. A subset of IS-124
NSDU Network Service Data Unit
NSEP National Security and Emergency Preparedness. People who are eligible for PAS/PACA
NSN National Significant Number. All of an E.164 number apart from the CC, i.e. NDC + SN
NSS Network and Switching Subsystem
NSTAC US National Security Telecommunications Advisory Council
NT Network Termination
NTIA U.S. Dept. of Commerce National Telecommunications and Information Administration
NTS Number Translation Service
Number Pooling Sharing a block of numbers between carriers. In the NANP this means that a block of 10,000 numbers is shared (currently in multiples of 1,000) by several carriers. Pooling is implemented using LNP
Number Porting See LNP or WNP
NVSE Normal Vendor Specific Extension
NXX Digits 4-6 of a NANP directory number. N can be any digit 2-8, while X can be any digit 0-9


O-BCSM Originating BCSM
O/E Odd/Even
O&M Operations and Maintenance
OA&M Operations, Administration and Maintenance
OAA Over-the-Air Activation. See OTA
OAM&P Operations, Administration, Maintenance and Provisioning
OATS Over-the-Air Activation Teleservice. See TIA/EIA-136
OBF Ordering and Billing Forum of ATIS
OC-1 SONET service at 51.84 Mbps. Equivalent to one DS3 (672 DS0)
OC-12 SONET service at 622.08 Mbps. Equivalent to 12 DS3 or 8,064 DS0
OC-18 SONET service at 933.12 Mbps. Equivalent to 18 DS3 or 12,096 DS0
OC-192 SONET service at 9.95328 Gbps. Equivalent to 192 DS3 or 129,024 DS0
OC-24 SONET service at 1.24416 Gbps. Equivalent to 24 DS3 or 16,128 DS0
OC-3 SONET service at 155.52 Mbps. Equivalent to 3 DS3 or 2,016 DS0
OC-36 SONET service at 1.86624 Gbps. Equivalent to 36 DS3 or 24,192 DS0
OC-48 SONET service at 2.48832 Gbps. Equivalent to 48 DS3 or 32,256 DS0
OC-768 SONET service at 38.813 Gbps. Equivalent to 768 DS3
OC-9 SONET service at 466.56 Mbps. Equivalent to 9 DS3 or 6,048 DS0
OC-96 SONET service at 4.97664 Gbps. Equivalent to 96 DS3 or 64,512 DS0
OCDM Optical Code Division Multiplexing
OCH Optical Channel
OCN Operating Company Number. US identifier for a telecom carrier
OCS Online Charging System. Used for real-time charging (e.g. prepaid).
OCSP Online Certificate Status Protocol. An IETF protocol
octet A snooty standards term for byte
ODB Operator Determined Barring
OEC(1) DHS Office of Emergency Communications. Supports and promotes the ability of emergency responders and government officials to continue to communicate in the event of natural disasters, acts of terrorism, or other man-made disasters, and works towards interoperable and operable emergency communications nationwide.
OET US FCC Office of Engineering & Technology
OFA Optical Fiber Gateway
OFDMA Orthogonal FDMA
OG Optical Gateway
OHG Operators Harmonization Group. A group of wireless carriers that wants to make CDMA systems work on both ANSI-41 and GSM networks
OLA Optical Line Amplifier
OLC Overload Control
OLI Originating Line Indicator. ISUP parameter that identifies the class of phone (e.g. residential, payphone, hotel/motel)
OLNS Originating Line Number Screening (using LIDB)
OLT Optical Line Termination
OMA Open Mobile Alliance
OMC Operations and Maintenance Center
OMNCS Office of the Manager, NCS
OMT Overhead Message Train (messages transmitted from base station on the analog Control Channel)
ON Optical Network
OPC Originating Point Code. Where an SS7 message came from
OPDU Operation PDU
OpenH323 A project to create an open source implementation of H.323
OPSP Origination Participation Service Provider
OPTS Over-the-Air Programming Teleservice. See TIA/EIA-136
Originating MSC The first MSC involved in a mobile terminated call. Either a Gateway MSC or the Home MSC
Origination The process of starting a call, usually initiated by dialing digits
ORREQ TIA/EIA-41 OriginationRequest transaction
OSA 3GPP Open Service Access. Enables third parties to use network functionality through an open standardized interface (OSA API)
OSA-AS OSA Application Server
OSA-SCS OSA Control Server
OSF Operations Systems Function
OSI French synonym for ISO
OSPF Open Shortest Path First IP routing algorithm.
OSS(1) Operations Support Subsystem
OSS(2) Operator Services Switch
OTA Over-the-Air programming. Uploads internal mobile tables or software.
OTAF Over-The-Air Activation Function. A specialized MC for performing OTASP and OTAPA
OTAPA Over-The-Air Parameter Administration. A network initiated form of OTA
OTASP Over-the-Air Service Provisioning. A mobile-initiated form of OTA
overdial The process of dialing a phone number during an established call, when the original number dialed was to access some kind of gateway system. See Roamer Port
OWF One Way Function. A function that is much easier to perform than to invert (i.e. back-calculate). This concept is the foundation of much of modern cryptography
OXC Optical Cross Connect


P-CSCF Proxy CSCF. First contact point for a terminal within the IMS
P-P PDSN to PDSN interface used to support fast handoff (tunneling of packets from old serving system to new serving system).
PAC PPTP Access Concentrator. Concentrates PPP traffic on a dial access platform. See PNS
PACA Priority Access and Channel Assignment. Channels are assigned to mobiles attempting to originate a call in order of priority, rather than first-come, first-served. See PAS
Packet data Data transmitted from multiple users in individually address discrete packets. Compare with CSD
PACS Personal Access Communications System
PAD Packet Assembly/Disassembly
Page The process of telling an MS to prepare for an incoming call
PAMR Public Access Mobile Radio. A wide-area form of PMR that provides group-oriented communications (such as PTT) to the public, rather than being run for a single organization. See SMR.
PAN Personal Area Network. A network that connects personal devices, such as computer, keyboard, mouse, phone and monitor. Also known as Piconet
PANID Previous ANI
PAP Password Authentication Protocol. A simple authentication protocol that sends security information in the clear. Compare with CHAP
Parlay/OSA Open Service Access/Architecture. An API that enables operator and 3rd party applications to make use of network functionality through a set of open, standardised interfaces. Implementations are JAIN SPA, OMG-IDL and WSDL
PAS Priority Access Service. See PACA
PBCCH GPRS Packet Broadcast CCH
PBX Private Branch Exchange. A privately owned switch providing wired and possibly also wireless service for an office, factory, campus, etc.
PC Personal Computer
PCAP UTRAN Positioning Calculation Application Part
PCCCH GPRS Packet Control Channel
PCF Packet Control Function. Obsolete. See PDF
PCG 3GPP Project Coordination Group
PCH Paging Channel
PCI Protocol Capability Indicator
PCIA Personal Communications Industry Association. Rival trade association to CTIA
PCM Pulse Code Modulation. The encoding scheme for digital voice in a circuit-switched telephone network.
PCMCIA Personal Computer Memory Card International Association
PCN Personal Communications Network. See PCS
PCS Personal Communications System. See DCS, PCS1900
PCS1900 North American PCS frequencies, 1850-1990 MHz. See DCS
PCSC Personal Communications Switching Center. See MSC
PD Packet data
PDA Personal Digital Assistant
PDC Pacific Digital Cellular. A Japanese cellular standard based on GSM operating in the 800 MHz and 1500 MHz frequency bands.
PDC-P PDC Packet network used
PDCP UTRA Packet Data Convergence Protocol
PDD Post-Dial Delay. The delay between dialing and having the call cut through to the party at the other end
PDE Position Determining Entity
PDF Policy Decision Function
PDG PD Gateway. Similar to PDSN.
PDH Plesiochhronous Digital Hierarchy
PDLP PD link protocol
PDN Public Data Network or Packet Data Network
PDP PD Protocol
PDREG Power-Down Registration
PDSN Packet Data Serving Node. Not to be confused with PSDN
PDU Protocol Data Unit
PEAP Protected EAP. A more secure version of LEAP developed by Microsoft and Cisco.
pen register A form of surveillance where dialed digits and time of call are collected
Penetration The percentage of the population of a service area (POP) that have acquired a certain service
PER(1) Packed Encoding Rules. Avoids the TLV overhead of BER and TCAP
PER(2) Packet Error Rate. The fraction of packets that have one or more errors. Compare with BER.
pESN Pseudo ESN. Formed from the 8-bit prefix 0x80 followed by the 24 least significant bits of the SHA-1 extract of the MEID. See also tESN and pUIMID.
Peta Prefix to indicate one thousand trillion (e.g. Peta-bit). Abbreviated P
PH Packet Handler
PHB Per-Hop Behaviour
PHP(1) PHP Hypertext Preprocessor. Yes, this is a recursive acronym.
PHS Personal Handyphone Service. A real success until people found that it was not true cellular service
PI Polling Indicator
PIC(1) Preferred Inter-exchange Carrier Code. Identifies the long distance carrier for a subscriber. Generally national in scope
PIC(2) Point in Call. An IN, WIN, CAMEL term
Piconet See PAN
PIN Personal Identification Number. Used to restrict access to personal services or capabilities
PINT PSTN and Internet Interworking - IETF WG. See RFC 2848
PISN Private Integrated Services Network. Composed of inter-connected PBXs.
PIX(1) Proprietary application Identifier eXtension. See AID and RID.
PKC Public Key Cryptography. Also known as Asymmetric Key Cryptography
PKE Public Key Encryption
PKI Public Key Infrastructure
PL Physical Layer
Plaintext Unencrypted data. Compare with Ciphertext
PLCM Used for encoding cdma2000 conversations on the reverse traffic channel. Originally based on the ESN of an MS it now can be assigned by the BS or calculated from the IMSI or MEID.
PLMN Public Land Mobile Network. A cellular, PCS or 3G wireless network
PM(1) Privacy Mode
PM(2) Personal Mobility
PMN Public Mobile Network. Synonym for PLMN
PMR Professional/Private Mobile Radio. A radio system established to service a single organization or group of related organizations. They usually provide special group communications capabilities, such as PTT. See SMR. Contrast with PAMR
PN(1) Pseudo-Noise. Orthogonal code used to separate CDMA transmissions
PN(2) Project number
PN Sequence A defined repetitive sequence of binary bits, typically quite long. PN sequences are often used to test digital communications systems because they are composed of typical data patterns (as opposed to, say, alternating 1s and 0s) but are nonetheless defined bit-by-bit, so that the correctness of received bits can be determined at the receiver. PN sequences are also used extensively in the channel structure of many wireless technologies such as CDMA.
PNA Presence Network Agent
PNG Portable Network Graphics. A web graphics format using lossless compression (and decompression) and 48 bit color (unlike JPEG). Its proponents believe that it will also replace GIF and TIFF.
PNP Private Numbering Plan
PNS PPTP Network Server. See PAC
PoC Push/Press-to-Talk over Cellular. Refers to systems running over standard cellular systems that emulate the push-to-talk system of iDen and similar systems. See PTT.
POCSAG A paging protocol that runs at 512 or 2400 bps. Compare with FLEX, ReFLEX.
POI Point of Interconnect
Point Code A numeric SS7 address. 24 bits in the NANP, 16 bits in Japan, and 14 bits in most other countries
Pooling The ability to share a block of 10,000 NANP phone numbers between carriers. See ITN and Thousands block pooling
POP(1) Population of a service area. Licenses are often valued based on this
POP(2) Point of Presence. A place where a carrier provides connectivity to its network
POP3 Post Office Protocol Version 3. IETF RFC 1939
Port-in The porting of a number from the perspective of the new service provider. See LNP and WNP
Port-out The porting of a number from the perspective of the old service provider. See LNP and WNP
Portable Block A block of 10,000 NANP directory numbers that contains at least one Ported DN
Portal A fancy name for a web page that provides a single point of entry for a suite of web services
Ported DN A DN that has been ported from one carrier to another. See LNP and WNP
POS(2) Packet over SDH
POS (1) Personal Operating Space. A space about a person or object about 10 meters in radius that envelopes the person. See WPAN
POTS Plain Old Telephone Service (incoming and outgoing calls, but no fancy features)
PPDR Public Protection and Disaster Relief
PPDU Presentation PDU
PPP(1) Point-to-Point Protocol. IETF RFC 1661. Provides a reliable link to the internet over a single-user facility (e.g. phone line) that can carry several network protocols simultaneously. See PPP, PAP, CHAP
PPP(2) Peripheral Pre-Processor
PPTP Point-to-Point Tunneling Protocol. Allows PPP to be tunneled through an IP network. Uses an enhanced GRE mechanism for flowcontrol and congestion control. Defined in RFC 2637. May be replaced by L2TP
PQoS Position QoS. The desired/required/measured quality of position measuring accuracy and delay
PRACK IETF SIP Provisional Acknowledgement message
PRAMP Power Ramp
PRBS Pseudo-Random Binary Sequence
PRC(1) Premium Rate Charging
PRC(2) Primary Reference Clock
PRC(3) People’s Republic of China
Prepaid wireless Wireless services paid for in advance, as opposed to monthly billing. Technical challenges limit the services available, such as roaming and international calling
PRI Primary Rate Interface (1.544 Mbps). See T1, DS1
Private long code mask Used for encrypting TIA/EIA-95 conversations. Based on secret key information
PRL CDMA Preferred Roaming List. A database within an MS that prioritizes the systems that the mobile might encounter while roaming.
PRN Provide Roaming Number
Protocol A specification of the messages used to communicate over one or more Interface
PS(1) Packet Switch(ed)
PS(2) Priority Service. See WPS, PACA
PS(3) Positioning Server.
PSAP Public Service Answering Point. The place where 9-1-1 calls are answered
PSCR(1) Public Safety Communications Research. A joint project between NIST/OLES and NTIA/ITS within the US Department of Commerce.
PSD Power Spectral Density
PSDC WAG Persistent Storage Drafting Committee. A WAP Working Group
PSDN Packet/Public Switched Data Network. Not be be confused with PDSN
Pseudolite(1) A GPS ground station that transmits a signal similar to a satellite that might not be visible to all GPS devices.
PSI PCF Session ID
PSID Private SID. Used to identify a virtual private wireless system (e.g. wireless PBX)
PSK(1) Phase Shift Keying. Information bits are identified by changes in phase of the carrier. Usually, the signal is split into two parts. I is unchanged, and Q is phase shifted by 90 degrees. Phase can be controlled by the amount of each path that is remixed upon output
PSK(2) Pre-Shared Key.
PSMM Pilot Signal Strength Message. Used for CDMA triangulation
PSN Packet Switched Network
PSPDN Packet Switched PDN
PSS 3GPP Packet Streaming Service.
PSTN Public Switched Telephone Network. The 'phone system'.
PSVT Packet-Switched Video Telephony
PTM Point-to-Multipoint (Broadcast)
PTP Point-to-Point
PTT Push To Talk. Pressing a button on a phone initiates communications with a pre-defined group of other users. The system will usually give one radio the ability to transmit, and the remainder can only listen until the button is released or the phone exceeds the maximum time limit on the right to talk.
Public long code mask See PLCM.
PUC(1) GSM Personal Unblocking Code. A code provided by a carrier to regain access to a SIM that has become locked due to multiple entries of an invalid PIN. If this code is entered incorrectly 10 times, the SIM will become permanently inoperable and must be replaced.
pUIMID Pseudo UIMID formed from the 8 bit prefix 0x80 and the least significant 24-bit SHA-1 extract of the EUIMID.
PUK(1) GSM Personal Unblocking Key. See PUC.
PUREG Power-Up Registration
PV Protocol Version
PVC Permanent VC
PVI PV Indicator
PZID Packet Zone ID


QAM Quadrature Amplitude Modulation. A method of encoding a digital symbol in an analog symbol using combinations of phase and amplitude that are modulated at right angles to the main carrier. See 8QAM, 16QAM, 32QAM, 64QAM, 128QAM
QCELP Qualcomm Code Excited Linear Prediction
QoE Quality of Experience. The subscriber's perception of their quality of service.
QoR Query on Release. A method for implementing LNP
QoS Quality of Service. A list of measurable attributes such as bandwidth, delay and jitter that should be met for a specific communications service
QPSK Quadrature PSK used in CDMA. Phase can be in one of four states
QSIG ISDN based signaling inter-PBX protocol.
Quintet A group of 5 security data elements used in AKA. Composed of RAND, expected user response (XRES), Cipher Key (CK), Integrity Key (IK) and network authentication token (AUTN)


R and R Revise and Resubmit. The usual treatment for a contribution to a standards committee
R-APDU Response APDU
R-P Interface between a PDSN and a PCF that uses a GRE tunnel to carry user data and signaling messages.
R-SCH Reverse SCH (from MS)
R-SGW Roaming SGW. Interface between SS7 SCCP and MTP to IP protocols
R-UIM Removable UIM
RA Registration Authority
RAB Radio Access Bearer
RAC Routing Area Code. An 8 bit number identifying a routing area with a location aarea
RACF Radio Access Control Function. An IN term
RACH Random Access Channel. Mobiles compete to access this shared Control Channel
Radio Frequency Electro-magnetic radiation having a frequency in the range used for telecommunications, greater than that of the highest audio-frequency and less than that of the shortest infra-red waves.
Radio Interface The interface between an MS and a BS
RADIUS Remote Authentication Dial-In User Service. An internet user authentication system. See IETF RFC 2138, 2139 and AAA
RAI GSM Routing Area Identification. Composed of LAI + RAC
RAKE A receiver technique which uses several baseband correlators to individually process several signal multipath components. The correlator outputs are combined to achieve improved communications reliability and performance
RAN Radio Access Network
RANAP UTRAN RAN Application Part
RAND Random number used for authentication purposes
RANDBS Random number used for base station challenge authentication operation. See CAVE
RANDC RAND Confirmation. A portion of RAND used to try to confirm the value that was used by an MS during a Global challenge
RANDSSD Random number used for CAVE SSD Update operation
RANDU The random number used for a Unique Challenge
RAO Revenue Accounting Office
RASC Radio Access System Controller. An IN term
RAT Radio Access Technology. Used to distinguish between GPRS and UMTS in 3GPP networks.
Rate Center The location of a phone for billing purposes. Long distance charges are calculated based on the distance between two rate centers (often the switch location). Rate centers and competition combine to cause very inefficient number assignment, because every carrier operating in a rate center must be assigned at least 10,000 numbers. But, see Pooling
RATI Random ATI. Compare with UATI
RBOC Regional BOC. One of 7 local exchange companies formed from the breakup of AT&T: NYNEX, Bell Atlantic, BellSouth, Southwestern Bell, Pacific Bell, US West and Ameritech
RCF Radio Control Function. An IN term
RD Requirements Document
RDF Resource Description Format
RDTC Reverse DTC
RDV Roamer Database Verification (IS-847). Ability of HLR to query VLR database to determine whether information needed to support roamers is correct
REAG Regional EA Grouping. A geographical area (encompassing several EAs) used to license the AWS B, C and E bands.
RECC Reverse Analog Control Channel
Recipient Switch The switch to which a number has been ported. See LNP
RED Random Early Detection
Reed-Solomon A type of FEC
ReFLEX A two-way paging protocol related to FLEX. Operates at speeds up to 9600 bps inbound and 6400 bps outbound (25 kHz channel) or 25600 bps (50 kHz channel)
Registration The process where an MS informs a system of its presence
Rel(1) Abbreviation for release of a specification (e.g. GSM Rel 5)
REL(2) SS7 ISUP circuit Release message
Release Returning a trunk, transceiver or other telephony resource to the idle list
RES Authentication response. A value calculated from at least a secret key and a random number, that can be used to infer that the respondent is in possession of the secret key, without revealing it.
REST(1) Representational State Transfer. A style of communications design that uses existing capabilities of protocols (such as HTTP) to accomplish relatively simple machine-to-machine communications. Contrast with SOAP.
RETURN RESULT Message sent to successfully end TCAP transaction
REVAL Recommendations on the Procedures for Evaluation of Radio Transmission Technologies for FPLMTS
Reverse 911 Dialing up all landline phones within a geographical area to deliver a recorded message, e.g. about a weather emergency. This is usually a voluntary service
Revertive dialing Calling your own phone number. Often used to access a voice mail system
RF Radio Frequency
RFC IETF Request for Comments. Internet standard (well, not officially, but in practice many internet ‘standards’ are still just RFCs)
RFI(1) Request For Information
RFI(2) Radio Frequency Interference
RFID Radio Frequency Identification. A small chip that is designed to allow the identification and tracking of an object (e.g.manufactured item, airline bag).
RFP Request for Proposal
RFU Reserved for Future Use
RIH Rate Input Handler. Puts a price on usage (e.g. a phone call)
Rijndael Encryption algorithm chosen for AES (replacement for DES). Means 'Rhine Valley' in Flemish. Pronounced 'Rain Doll' (while clearing your throat)
RIL3 GSM Radio Interface Layer 3
RIP Routing Information Protocol. Compare with OSPF
RLC Radio Link Control
RLH Rate Load Handler. Loads rated transactions into the billing system and monitors the usage limits (e.g. for prepaid, fraud analysis)
RLP(1) Radio link protocol
RLP(2) OMA/3GPP Roaming Location Protocol between SUPL Location Platforms (SLP).
RN Radio Network
RNC Radio Network Controller
RNS Radio Network Subsystem
RNTI Radio Network Temporary Identity. See TMSI
ROA Registered Operating Agency
Roamer A mobile that is present in a system (MSC-V) that is not its home system
Roamer Port A phone number that allows Termination to a Roamer via the MSC-V
ROER Remote Operation Error. See ROSE
ROHC RObust Header Compression (and, if you’re lucky, decompression). RFC 3095. Provides compression of IP, UDP, RTP and ESP headers using W-LSB. In future, compression of TCP, SIP and other header types is also planned. It is more robust than CRTP
ROIV Remote Operation Invoke. See RORJ
RORJ Remote Operation Reject. See ROIV
RORS Remote Operation Result
ROSE Remote Operations Service Element. A message packaging protocol
Router An IP packet switch. Compare with STP
RPC(1) Radio Port Controller. An IN term
RPC(2) Remote Procedure Call. A method of exchanging data between applications running on different machines. Compare with SOAP
RR(1) Radio Resource
RR(2) Resource Record. Basic storage element for DNS
RRC RR Control
RRM RR Management
RRP MIP Registration Reply
RRQ MIP Registration Reply Request
RS Reed-Solomon error correction code
RSA(1) Rural Statistical Area. CGSA for rural cellular systems. Also used for licensing the FCC AWS D band.
RSA(2) Rivest, Shamir and Adleman PKE algorithm. Also the name of a corporation based on commercialization of this algorithm
RSID Residential SID. Used to identify a virtual residential wireless system
RSN Robust Security Network. The long-term security enhancement for WiFi that replaces both WPA and WEP.
RSS Received Signal Strength. A measure of the strength of a radio signal
RSSI Received Signal Strength Indication. Used to determine when a Handoff should be attempted
RSVD Reserved
RSVP IETF Resource Reservation Protocol. RFC 2205. A control protocol for assigning bandwidth to packets based on their desired QoS
RTCP RTP Control Protocol.
RTF Radio Terminal Function. An IN term
RTP(1) ISUP Release to Pivot Capability. Allows a call connected to one switch to be redirected to another by dropping back to an earlier switch to optimize trunking
RTP(2) IETF Real Time Protocol. Used by SIP, among other protocols
RTSP Real Time Streaming Protocol
RTT(1) Radio Transmission Technology candidate for IMT-2000
RTT(2) Round trip time. The time for a message to get from origin to destination and back again. For communications based on the exchange of many small messages this is more important than the actual bandwidth.
RTT(3) Abbreviation for 1XRTT
RVC Reverse analog Voice Channel
RX Abbreviation for receive or receiver
RXP A protocol that bridges ReFLEX networks together. Based on XML, HTTP and TCP/IP. See WCTP
RZ Return to Zero


S-CSCF Serving CSCF. Handles IMS session states
S-SCM Serving SCM
S/N Signal to noise ratio
S/R Emergency services selective router
SA Security Association
SA1 3GPP TSG SA Working Group 1 for Service Specifications.
SA2 3GPP TSG SA Working Group 2 for Architecture Specifications.
SA3 3GPP TSG SA Working Group 3 for Security Specifications.
SA4 3GPP TSG SA Working Group 4 for Codec Specifications.
SA5 3GPP TSG SA Working Group 5 for Telecom Management.
SAAL Signaling ATM Adapatation Layer. Equivalent of MTP layer 2 for ATM networks used to carry SS7 traffic. Includes SSCF, SSCOP and MAAL
SABM Set Asynchronous Balanced Mode
SACCH Slow Associated Control Channel. A control channel that is transmitted at a low bit rate in parallel with digitized voice.
SAFER Safe And Fast Encryption Routine. Based on IBC
SAIC Single Antenna Interference Cancellation
SAMPS ANSI-136 System Assisted Mobile Positioning through Satellite. TDMA, MS-assisted location determination, using GPS
SAP Service Access Point. Identifies a particular user service, sending and receiving a specific class of data.
SAPI SAP Identifier. Assigned by IANA.
SAR(1) Segmentation and Reassembly
SAR(2) Successive Approximation Converter. Type of analog-to-digital converter
SAR(3) Specific Absortion Rate. Amount of RF energy absorbed (e.g. for RF/health studies)
SASL Simple Authentication and Security Layer. IETF RFC 2222
SAT(1) Supervisory Audio Tone. One of three tones around 6 kHz that are transmitted from a base station to an MS by analog cellular (EIA/TIA-553)
SAT(2) SIM Application Toolkit
SC Steering Committee
SCADA(1) Supervisory Control and Data Acquisition.
SCC(1) SAT Color Code. A slight variation in frequency to limit false SAT detection
SCC(2) Service Control Code. A 1, 2 or 3 digit code followed by an asterisk (*) used for controlling switch capabilities during a call (e.g. 777*). Compare with FC
SCCP Signaling Connection Control Part. SS7 enhanced routing and identification layer
SCE Service Creation Environment for the Intelligent Network (IN, WIN)
SCEG Smart Card Expert Group. A WAP Working Group
SCEMA Secure Cellular Encryption Module Algorithm
SCF Service Control Function. Most important part of an SCP
SCH(1) CDMA Supplemental Channel. Used for transmitting higher speed data
SCH(2) GSM Synchronisation Channel; downlink only frame synchronisation and identification of base station.
SCID Subchannel Identity
SCM(1) Station Class Mark. Identifies the power class and transmission mode of an AMPS terminal
SCM(2) 3GPP2 Session Control Manager. Manages multimedia sessions. Obsolete. See CSCF
SCP Service Control Point. An SS7 network element used to control call processing (e.g. by providing database or intelligent network services)
SCPT CDMA Service Category Programming Teleservice
SCR Static Conformance Requirements
SCTP Stream Control Transmission Protocol specified in IETF RFC 2960. Similar to TCP, it differs in supporting multiple independent streams of packets which prevents a failure in one stream backing up packets in all streams.
SCVP Simple Certificate Validation Protocol. Allows a simple device to send a certificate to a server for validation. An IETF draft
SDB Short Data Burst
SDCA Indian Short Distance Charging Area
SDCC Supplementary DCC
SDCCH GSM Standalone Dedicated Control Channel.
SDF Service Data Function (IN term)
SDFU Sub-rate Digital Facility Unit
SDH Synchronous Digital Hierarchy
SDL Specification Description Language
SDL(2) System Design Language
SDO Standards Development Organization. The TIA and ATIS are SDO's
SDP IETF Session Description Protocol that describes multimedia sessions for the purposes of session announcement, invitation, and other forms of multimedia session initiation. See SIP
SDR(1) Software-Defined Radio. A radio that can operate in different modes (e.g. frequency bands, modulation schemes) based on the software that is currently loaded and active in the device.
SDR(2) Special Drawing RIghts. A virtual currency used for exchange of billing information between carriers.
SDSL Symmetric DSL. Bit rates are the same in both directions
SDU(1) Selection and Distribution Unit. Part of a base station that contains the voice coders
SDU(2) Service Data Unit
segmentation The process of breaking a long protocol message into pieces that are no longer than the maximum allowed by lower protocol layers. Oh, and reassembling them later!
Sensitivity The ability to receive a radio signal very near to the thermal noise level. The more sensitive the receiver, the lower the required incident radio signal required for acceptable reception.
SerG GSMA Services Group
Serving MSC The MSC currently serving an MS
SET SUPL Enabled Terminal. Supports the location procedures of SUPL, interacting with the network over the user plane bearer.
Settlement The process of exchanging revenue between telecommunications carriers
SF Superframe
SF_EUIMID(1) Short Form EUIMID. Based on the MEID format and allocated from the same numbering space. However, the SF_EUIMID of an R-UIM will never be the same as the MEID of the phone that it is inserted into.
SFI Short File Identifier in a UIM or SIM
SG(1) ITU Study Group
SG(2) Signaling Gateway. Converts an internet protocol to another protocol, e.g. SS7
SG(3) GSMA Security Group
SGCP Simple Gateway Control Protocol. A VoIP call control standard. Also see MGCP
SGML Standardized Generalized Markup Language. The father of XML
SGSN Serving GSN
SGW Signaling Gateway
SHA-1 Secure Hash Algorithm. Produces a condensed representation ('hash') of a string of bits (e.g. protocol message). Because it is computationally infeasible to determine the original text knowing the digest it is useful in authentication algorithms. Because it is also infeasible to find two strings that produce the same digest, it is also useful in digital signing algorithms. See MD5.
SHDSL Single-pair high speed DSL
SID System Identifier. A 15 bit identifier of an AMPS wireless license or system
SIF Signalling Information Field. The payload of an SS7 MTP message
SIG Special Interest Group
Signaling Messages used to control calls, assign resources, maintain and monitor telecommunications systems
SIM(1) GSM Subscriber Identification Module (Smart Card). Compare with UIM
SIM(2) Service Interaction Manager. A WIN concept
SIMPLE SIP for IM and Presence Leveraging
SIN Specification Information Node
SINAD Signal + Noise + Distortion
SIP Session Initiation Protocol. An IETF IP protocol for VoIP (packetized voice) call processing. See SDP.
SIP-AS SIP Application Server
SIP-T Variant of SIP that encapsulates ISUP signaling to provide support for circuit-switched communications
SKey Session Key
SLA Service Level Agreement. A carrier agrees to provide a certain level of service (e.g. availability, bit rate, voice quality) and provide significant discounts if the levels are not met
SLC SUPL Location Center. Coordinates the operations of SUPL in the network.
SLEE Service Level Execution Environment
SLF 3GPP Subscription Locator Function
Slow Fading Fade duration long relative to channel frame length
SLP(1) Service Logic Program
SLP(2) SUPL Location Platform. Consists of an SLC and an SPC.
SLS Signaling Link Selection
SM Session Management
SM-MT Mobile Terminated Short Message
SM-SC Short Message Service Center (see MC)
Smart Card See UIM, SIM
SMCK OTA Secure Mode Ciphering Key. Allows for the encryption of provisioning data that is going to be transmitted over a radio interface
SMDPP TIA/EIA-41 SMS Delivery Point-to-Point message
SMDS Switched Multimegabit Data Service
SME(1) Short Message Entity (SMS terminal)
SME(2) Signaling Message Encryption
SMG Subject Matter Group
SMIL Synchronised Multimedia Integration Language
SMLC Serving MLC
SMPP Short Message Peer-to-Peer Protocol. Promoted by the SMPP Forum
SMR Specialized Mobile Radio. A form of private mobile radio that allows one talker and multiple listeners in a group (e.g. taxi company)
SMS(1) Short Message Service
SMS(2) Service Management System. Communicates number portability (LNP) and pooling information between carriers.
SMS-C GSM SMS Center. See MC
SMSCB See Broadcast SMS
SMSCH SMS Point-to-Point Channel
SMSEG WAP SMS Expert Group
SMTP Simple Mail Transmission Protocol defined in IETF RFC 2821
SMV CDMA Selectable Mode Voice Coder
SN(1) Service Node. A combination of SCP and IP functionality
SN(2) E.164 Subscriber Number
SNDCP Sub-Network Dependant Convergence Protocol
SNMP Simple Network Management Protocol. Network management protocol usually used with TCP/IP networks, and others
SNR(1) See S/N
SNR(2) Serial number. The unique 6 digit number assigned to a GSM phone within an IMEI
SNS(1) Social Networking Services
SOA Service Order Activation. For LNP, this represents an interface between a carrier and the NPAC SMS
SOAP Simple Object Access Protocol. XML based language for exchanging data between internet applications on different machines. Bypasses firewalls by being disguised as XML/HTML. Compare with CORBA and RPC. Contrast with REST.
SOC System Operator Code. Used in IS-136 TDMA digital systems to identify the wireless carrier
SOHO Small Office/Home Office
SoLSA Support of Localized Service Area
SONET Synchronous Optical Network
SoR Statement of Requirements.
SP(1) Signaling Point. An SS7 network node: SCP, SSP or STP
SP(2) ANSI standards proposal number
SPA JAIN Service Provider APIs
SPASM Subscriber Parameter Administration Security Mechanism
SPC SS7 Signaling Point Code. Also PC
SPDU Session PDU
SPI Service Provider Identification
SPINA Subscriber PIN Access
SPINI Subscriber PIN Intercept
SPL Service Programming Lock. A method of preventing a mobile from changing from the service the subscriber has contracted with
SPMC Signaling Point Management Cluster
Spool Simultaneous Peripheral Operations On-Line. Writing a print or other file to a special area of memory or disk so that it can be printed (or otherwise processed) while other computer operations are ongoing.
SPS Serving PS
SPS Serving PS
SQM Subscription Quality of Service Manager
SQN Sequence number (used for authentication/encryption). Its use can prevent replay attacks, where the same information is transmitted by a fraudulent device as by the legitimate device.
SRC WAP Specification Requirements Committee
SRD CTIA Standards Requirement Document
SRES Expected response to authentication challenge for GSM authentication. Compare with AUTHR
SRF Service Resource Function. Most important part of an IP
SRNC Serving RNC
SRNS Serving RNS
SS Supplementary/Supplemental Service
SS7 Signaling System Number 7 (common channel telecommunications packet switching)
SSCF Service-Specific Coordination Function. Maps between SAAL and higher layer protocols (e.g. SS7 MTP Layer 3). This includes responsibility for link changeover and flow control See ATIS T1.645
SSCOP Service Specific Connection-Oriented Protocol. Part of SAAL that provides reliable point-to-point communications with sequencing, retransmission on error, flow control, keep-alive, connection control. See ATIS T1.637.
SSD Shared Secret Data. A secondary key used in most CAVE operations
SSD-A Portion of SSD used for Authentication
SSD-B Portion of SSD used for voice, data and signaling encryption
SSF Service Switching Function. An IN term for a switch
SSID Service Set Identifier. An identifier of an 802.11 network.
SSL Secure Socket Layer. Secures TCP connections (e.g. for m-commerce)
SSN Sub-system number. Along with PC, identifies an SS7 network application or a virtual SS7 network entity
SSO Single Sign On. Having one set of authentication data to access many services.
SSP Service Switching Point (e.g. MSC). An SS7 SP that contains switching and signaling functions.
ST End of pulsing signal. An MF tone
Stage I The portion of a standard that describes the external behavior of a standard or capability
Stage II The portion of a standard that describes the flow of messages through a network to implement Stage I behavior
Stage III The portion of a standard that completely describes a protocol, to the level of bit encoding of messages and parameters, based on Stage II message flows
STK SIM Toolkit
STM Synchronous transport mode
STP SS7 signaling transfer point (i.e. packet switch). An SS7 SP that provides routing services. Compare with Router
STU-III Secure Telephone Unit - III. US government telephone encryption system
SUA SCCP User Adaptation Layer. Replaces SCCP and M3UA. Resides above SCTP and below the application in an IP telecom signaling protocol stack.
SUPL OMA Secure User-Plane Location architecture for LCS with intelligent, IP-enabled mobile devices.
surveillance Lawfully (hopefully) authorized monitoring of communications
SVC Switched Virtual (data) Circuit
SVLTE(1) Simultaneous Voice and LTE. The ME has an LTE radio for data and a CDMA radio for voice. See CSFB and VoLTE.
SVN GSM Software Version Number. A 2 digit code identifying a line of mobiles. See IMEISV
SVP Switched Virtual Path
SWAP Shared Wireless Access Protocol. Being defined by HRFWG. Operates in the 2.4 GHz ISM band. Abandoned in 2003.
SWG 3GPP Sub-Working Group
SYNC Synchronization
Synchronous Data that is transmitted as a regular, precisely clocked, stream of bits. A pattern of bits is used as a filler for times when there is no data to transmit. Compare with Asynchronous
SyncML A standard for synchronizing mobile devices.
Systemic Interference RF interference within a channel used in a wireless system that emanates from other elements of the system itself, and thus has predictable characteristics. For example, transmissions on the same channel form other base stations (intended for other mobiles). Contrast with Non-systemic Interference and Intermodulation Interference


T-BCSM Terminating BCSM
T1(1) Group of standards committees related mostly to wireline standards, such as SS7, but also North American GSM standards
T1(2) A digital link carrying 24 DS0 channels. Used mostly within North America. Compare with E1
T1A1 Renamed the ATIS Network Performance, Reliability and Quality of Service Committee in 2004.
T1E1 Renamed the ATIS Network Interface, Power, and Protection Committee in 2004.
T1M1 OA&M standards committee for North American wireline networks. Renamed as the ATIS Telecom Management and Operations Committee in 2004.
T1P1 Personal Communications (i.e. US GSM) standards committee for North America. Renamed the ATIS Wireless Technologies and Systems Committee in 2004.
T1S1 SS7 standards committee for North America. Split into the ATIS Packet Technologies and Systems Committee and the Protocol Interworking Committee in 2004.
T1X1 Renamed the ATIS Optical Transport and Synchronization Committee in 2004.
T3 Physical device carrying one DS3 service
TA(1) Terminal Adaptor
TA(2) Timing Advance. An adjustment in the time of cellular transmission based on the distance of a terminal from a base station. This can be used to estimate the distance of a terminal and determine its approximate location.
TAC(1) Total Access Communications. A name used by Motorola in several products, such as TACS, DataTAC
TAC(2) Type Approval Code. 6 digit part of IMEI that is assigned by a central authority (e.g. national telecom regulatory body)
TACS TAC System. Basically AMPS in the 900 MHz frequency band
TADIG GSMA Technology and Documentation Interoperability Group.
Tandem Any switch that is used to receive and route traffic (e.g. phone calls), but neither originates nor terminates them
TAP(1) Transfer Account Procedure. A billing record format used mainly by GSM carriers
TAP(2) Telocator (now PCIA) Alphanumeric Protocol for paging, now also used for SMS.
TAPS TETRA Adcanced Packet Service. A European data system based on GPRS and EDGE designed to work with TETRA. Ideal data performance is 600 kbps with frequency hopping and 466 kbps without. Defined by ETSI TS 101.962.
TAR Temporary Alternative Routing
Target MSC The destination MSC for an inter-system handoff
TAS(1) Telephony Application Server
TAU(1) Tracking Update. The equivalent of RAU for LTE.
TBCD Telephony BCD. Digit 0 is encoded as 10, as on a rotary dial phone
TCAP Transaction Capabilities Application Part. Message packaging standard used by TIA/EIA-41, LNP, 800 and other SS7-based applications. Defined in ANSI T1.114
TCB Telecommunication Certification Body. A national authority for the certification of radio devices.
TCC Telephony Country Code
TCG Trusted Computing Group
TCH Traffic Channel. Often classified as full rate(FR) or half rate (HR)
TCP Transmission Control Protocol. A protocol that provides for reliable delivery of messages over the internet. See UDP and IP
TCP/IP TCP used over IP
TD-CDMA TDD mode of operation for UTRA
TDD(1) Telephone Device for the Deaf. See TTY
TDD(2) Time Division/Domain Duplex. See TDMA
TDES Triple DES. An encryption algorithm with a strength of about 112 bits. See AES, DES.
TDM Time Division Multiplexing. See also TDMA
TDMA Time Division/Domain Multiple Access. Modulation technique used by D-AMPS and GSM
TDOA Time Difference of Arrival. See TOA and OTDOA
TDP Trigger Detection Point. See IN
TDS-CDMA Time Division Synchronization CDMA. Chinese 3G radio access proposal
TDSO CDMA Test Data Service Option
TE Data Terminal Equipment. A personal computer, for example
TEG WAP Telematics Expert Group
Teleservice A telecommunications service provided between two telecommunications terminals (e.g. a call between two phones or a short message between two wireless devices). Contrast with Bearer capability
Tera Prefix to indicate one trillion (e.g. Tera-bit). Abbreviated T
Termination The process of reaching the destination of a call. Not to be confused with Disconnection
tESN A unique ESN for a phone. See pESN, UIMID, pUIMID
TETRA Terrestrial Trunked Radio. A European PAMR system using 25 kHz channels.
TFO Tandem (or Transcoder) Free Operation. Elimination of the Voice Coder from a digital mobile-to-mobile call (assuming that both mobiles are capable of using the same type)
TFT Traffic Flow Template. Used to determine the QoS that applies to a specific packet.
TG Task Group of ITU-R
Thermal Noise Radio frequency noise associated with thermal activity. At a typical temperature of 300 degrees Kelvin (26.84 degrees Celsius), thermal noise is -174 dBm per hertz, or 114 dBm in a 1 MHz channel.
Thousands block pooling The ability to share a block of 10,000 NANP phone numbers in groups of 1,000 between carriers. Individual phone numbers within the block can then be ported (using LNP) to other carriers
throughput The actual traffic supported, as opposed to the raw bandwidth. Bandwidth that does not result in throughput may be due to packets containing errors, retransmissions, errorneous routing and many other causes. See goodput and badput
TIA Telecommunications Industry Association. A trade association that, among other things, defines standards for cellular and PCS, specifically AMPS, NAMPS, CDMA and TDMA
TIA-136 ANSI version of the TDMA air interface standard. Replaces IS-136 and TIA/EIA-136
TIA/EIA A prefix for a standard produced by the TIA in association with the EIA
TIA/EIA-124 Wireless call detail and billing record format for online transfer. Replaces IS-124
TIA/EIA-136 ANSI version of the TDMA air interface standard. Replaces IS-136. Replaced by TIA-136
TIA/EIA-41 Wireless intersystem operations standard. Previously called IS-41
TIA/EIA-41-D Intersystem Operations Standard. Replaces IS-41
TIA/EIA-634 A-interface standard between BS and MSC
TIA/EIA-93 Wireless-PSTN interface standard. Replaces IS-93
TIA/EIA-95 CDMA air interface standard
TIA/EIA-95-B Third generation CDMACDMA air interface standard. Replaces IS-95
TIFF Tagged Image File Format. Supports up to 24 bit color. Files tend to be large, but high quality. Perhaps because of the file size, it is not supported by many browsers. cf GIF, JPEG, PNG
TIPHON Telecommunications and Internet Protocol Harmonization over Networks
TISPAN(1) Telecoms and Internet Converged Services and Protocols for Advanced Networks. See
Title III A surveillance that is authorized to collect content (e.g. voice communications. Contrast with pen register and trap and trace
TKIP Temporal Key Integrity Protocol. A modification to WEP that increases security by frequently changing keys.
TL1 Telcordia (formerly Bellcore) MML language for telecommunications network monitoring.
TLDN Temporary Local Directory Number. A number used for routing calls from the Home MSC to MSC-V in ANSI-41. Compare with MSRN
TLLI Temporary Link Level Identity
TLS Transport Layer Security
TLV Tag, Length Value. Encoding of parameters by including an identifier (tag), length (of value) and the actual parameter contents (value). Used by BER and TCAP, for example. cf AVP
TM3 TIA committee for standardization of Terrestrial Mobile Multimedia Multicast. Created in 2005. Also known as TR-47
TMN Telecommunications Management Network. A network management protocol, used to logically define managed objects
TMO Trunked Mode Operation. A cellular-like mode of operation of a PAMR system. Compare with DMO.
TMSI Temporary mobile station identity. Used as a shorter, more private, mobile identifier. Identifies the system that assigned it, and not directly the MS
TMUI GSM term for TMSI
TNRN Terminating Network Routing Number
TOA Time of Arrival. A technique for location a radio by comparing the time of signal arrival at multiple points. Compare with AOA
TON Type of Number
TOS Type Of Service
TPDU Transport PDU
TPKT(1) An early version of ITOT.
TPP Terminating Party Pays. The mobile pays for airtime, whether it is making or receiving a call. cf CPP
TR(1) 3GPP Technical Report. These are informative, as opposed to TS
TR(2) TIA Technical Review standards committee prefix
TR-45 TIA Standards Committee responsible for AMPS-based cellular and PCS standards, including TDMA and CDMA digital
TR-45.1 TIA analog cellular standards subcommittee
TR-45.2 TIA Standards Subcommittee responsible for intersystem protocols
TR-45.3 TIA TDMA digital cellular/PCS standards subcommittee
TR-45.4 TIA BS/MSC "A" interface standards subcommittee
TR-45.5 TIA CDMA digital cellular/PCS standards subcommittee
TR-45.6 TIA CDPD standards subcommittee
TR-45.7 TIA OA&M cellular standards subcommittee. Now defunct.
TR-47 See TM3
Traffic Channel A portion of a radio channel used to transmit one direction of a digital voice conversation. Compare with Voice Channel
Transcoder(1) A device that converts a communication signal from one system to another, e.g. analog to digital or air interface digital to PCM.
Transcoding Conversion from one voice (or other media format) coder to another. Multiple transcoding operations can seriously reduce the end-to-end quality.
Transparent Data that is, to lower protocol layers, simply a sequenced collection of bits. Good protocol design tries to make all protocol layers transparent to all others, although often violations of this principal are necessary
trap and trace Collection of the identity of a part originating a call for surveillance purposes
TRAU Transcoding Rate and Adaptation Unit
TrFO Transcoding Free Operation. Establishment of a call without a transcoder.
Triplet A group of 3 security data elements used in GSM authentication. Composed of network challenge random number (RAND), expected user response (SRES) and Cipher Key (CK)
TS 3GPP Technical Specification. Normative, as opposed to TR
TSAR Teleservice segmentation and reassembly for TIA/EIA-136
TSB TIA Telecommunications Systems Bulletin. Often used as an addendum or erratum to a published interim standard
TSG Technical Specification Group. Part of the 3GPP and 3GPP2 processes
TSG CN 3GPP TSG for CN standardization
TSG GERAN 3GPP TSG for GSM standardization
TSG N 3GPP2 TSG for inter-system network protocols. Replaced by TSG-X.
TSG RAN 3GPP TSG for W-CDMA standardization
TSG S 3GPP2 TSG for service and system aspects (requirements, architecture, Stage 1 descriptions etc.).
TSG SA 3GPP TSG for defining services and architecture of W-CDMA 3G systems
TSG-A 3GPP2 TSG for the IOS
TSG-C 3GPP2 TSG for the cdma2000 radio interface
TSG-N 3GPP2 TSG for network procotols. Replaced by TSG-X
TSG-P 3GPP2 TSG for packet data protocols. Replaced by TSG-X
TSG-T 3GPP TSG for terminal and UIM standardization
TSG-X 3GPP2 TSG for the core network. Formed by the merger of TSG-N and TSG-P
TSI Time Slot Interchange
TT Translation Type. Defines the type of routing address used by GTT (e.g. E.164 directory number, E.212 IMSI etc.).
TTA Telecommunications Technology Association. Standardizes wireless network protocols in Korea
TTC(1) Telecommunication Technology Committee. Telecommunications standardization in Japan
TTC(2) Terminating Toll Center
TTCN Tree and Tabular Combined Notation. ISO/International Electrotechnical Commission IEC 646-3 is a notation for the specification of tests for communication systems. A TTCN–specified test suite is a collection of various test cases together with all of the declarations and components needed.
TTY A device used by the deaf or hearing-impaired to communicate text messages over telephone systems. It runs at 45.45 bps. See TDD
Tunnel An extra protocol addressing layer used to carry data where the inner addressing layer will not take it. Often used in IP, e.g. as part of Mobile IP or VPN
Tunneling Sending data transparently through a foreign network. Usually implies the use of a larger than optimal number of protocol layers
TUP Telephone User Part. Forerunner protocol to SS7 ISUP
TWG GSMA Terminal Working Group
TX Abbrevation for transmission or transmitter


U/L Uplink (e.g. from mobile to base station). Compare with D/L.
UA(1) User Agent. An application operating on behalf of a user device (e.g. phone or computer). See MM1.
UA(2) GSM Unnumbered Acknowledge
UAProf WAP UA Profiles Drafting Committee. Or a reference to the profiles that they generate.
UASL Indian Unified Access Services Licence. Replaces CMSP. This allows both GSM and CDMA carriers, as well as other technologies, to be implemented.
UATI Unicast ATI. A 128 bit address for a HRPD device. A 32 bit short version is available for transmission.. The AAA returns the IMSI or MIN to the serving network. Compare with RATI
UCP Universal Computer Protocol. Part of ERMES is an ETSI paging system . The most commonly used operations are: 01 - Call Input Operation; 03 - Call Input With Supplementary Services Operation; Operation 30 - SMS Message Transfer Operation; and Operation 51 - Submit Short Message Operation.
UDH Universal Data Header
UDP User Datagram Protocol. An internet protocol providing basic services only. Compare with TCP
UDR RADIUS Usage Data Record. Captures accounting data for packet data sessions.
UDT SS7 MTP unit data message. Carries a payload of about 250 octet
UDTS UDT service message. Used to send error responses to UDT messages
UE User Equipment (e.g. phone and all peripherals such as USIM)
UEA UMTS Encryption Algorithm. May be null (no encryption) or Kasumi
UGID User Group Identification
UHDM CDMA Universal Handoff Direction Message
UHF Ultra-High Frequency. 300-3000 MHz (used in the US and Canada as television channels 14-83)
UIA UMTS Integrity Algorithm. One possibility is Kasumi
UID User Interactive Dialog
UIM User Identification Module (Smart Card). See SIM
UIMID UIMESN(1) assigned to a UIM that supports CDMA operation. See tESN.
UL Uplink. Radio link in the direction 'up' to network. Compare with DL
ULDCH 3GPP Enhanced Uplink DCH
Um Radio interface between MS and BSS/BSC
UML ETSI Universal Modelling Language
UMTS Universal Mobile Telecommunications System (a 3G initiative). See It operates in 5 MHz channels at 3.84 Mcps with 200 kHz between channels.
UNI User-Network Interface
UNICODE A text encoding method that, by using more than 8 bits, can code special characters for many languages. Standardized as ISO 10646. Compare with ASCII, EBCDIC and ISO-8859-1
Unique Challenge A method of encryption using a unique random number (RANDU) as a challenge
Uplink Path from terminal to base-station
UPR CTIA User Performance Requirements document. Now know as SRD
UPT Universal Personal Communications
URI Uniform Resource Identifier. A superset of URL and URN. If an object is on the internet and does not have one of these it really doesn't exist.
URL Uniform Resource Locator. Form of internet address usable by a browser. Of the format ":". http, ftp and mailto are examples of schemes. The remainder of the URL is defined by the scheme, with some restrictions on the characters that can be used. Illegal ASCII characters can be included with the %XX notation, where XX is the two digit hexadecimal value of the character.
URN Uniform Resource Name
USAT USIM Application Toolkit
USCF User Selected Call Forwarding. Allows an incoming call to be diverted before it is answered, either to a preset number, or to a number specified at the time of diversion. Closely related to AH
USIM User Services Identity Module or Universal Subscription Identity Module. SIM for UMTS. See UIM
USSD GSM Unstructured Supplementary Service Data
Ut The 3GPP interface between the UE and AS.
UTC Universal Coordinated Time (don't ask)
UTM Universal Transverse Mercator.
UTRA Universal Terrestrial Radio Access.
UTRAN Universal Terrestrial RAN. The BS, BTS etc. for W-CDMA/UMTS
UU-SIGNAL User to User Signaling
UUID(1) Universally Unique Identifier. A 128 bit identifier based on the 48-bit MAC address or, if one is not available, generated randomly from a separate numbering space. The identifier also contains time information using a clock that does not roll over until 3400 AD. Defined in IETF RFC 4122
UWB A radio technology that uses short very high speed bursts of data over short distances. It is controversial because some claim that it can share spectrum with other users, and others claim that it will cause unacceptable interference.
UWC Universal Wireless Consortium. Promotes D-AMPS technologies around the world
UWC/136 TDMA digital cellular/PCS based on the IS-136 or TIA/EIA-136 standards
UWCC Universal Wireless Communications Consortium. Proponent of TDMA digital systems based on UWC/136. Disbanded at the end of 2001.


V and V Verification and Validation. A committee review of a standard before formal ballot
VA Validation Authority
VAAA Visited AAA
VAD Voice Activity Detection. A system that not only detects the absence of voice, and prevents transmission of unecessary digitized voice during this time
VAR Value-added Reseller
VAS Value Added Service
VASP VAS Provider. A company that provides a service (e.g. web content) without being the carrier.
VC Virtual Circuit
VCI VC identifier
VDSL Very high speed DSL, providing about 58 Mbit/sec in both directions. Available as asymetric (see ADSL) or symmetric (see SDSL). See VDSL Alliance
VDSL Alliance Promoters of VDSL
VGC Voice Group Call
VGCS Voice Group Call Service
VHE Virtual Home Environment
VHF Very High Frequency. 30-300 MHz (used in the US and Canada as television channels 2-13)
VLAN Virtual LAN. A subset of a LAN where files and services not available to a user are hidden.
VLR Visitor Location Register
VMAC Voice Mobile Attenuation Code
VMS Voice Message System
vocoder Voice Coder or codec
Voice Channel A radio channel used to transmit one direction of an analog voice conversation. Compare with Traffic Channel
Voice Coder Converts an analog voice signal into a digitally coded representation, and vice-versa. Wireless voice coders often also compress the voice into a bit rate from 8kbps to 13 kbps. Also called codec or vocoder
VoIP Voice over IP
VoLTE(1) Voice over LTE. Voice is handled as VoIP on an LTE data connection.
VP(1) Voice Privacy (i.e. encryption)
VP(2) Virtual Path
VPI VP Identifier
VPIM Voice Profile for Internet Mail
VPM Voice Privacy Mask
VPN Virtual Private Network
VSA RADIUS Vendor Specific Attribute. A field used to transmit data for a particular accounting application (e.g. cdma2000 packet data).
VSELP Vector Sum Excited Linear Prediction


W-CDMA Physical layer of the FDD mode of operation of UTRA. A ‘European’ version of CDMA and the 3G evolutionary step planned for GSM. Operates in pairs of 5 MHz channels at 3.84 Mcps
W-LSB Window-Based LSB encoding for IP header compression (and decompression). Part of ROHC
W3C World Wide Web Consortium
WADGPS(1) Wide Area Differential GPS. Provides signal correction information from a number of ground reference stations.
WAE Wireless Application Environment. See WAP
WAG(1) Wireless Applications Group
WAG(2) WLAN Access Gateway
Walsh codes A group of 2N vectors or words which contain 2N binary elements which with themselves and their logical inverses form a mutually orthogonal set.
WAN Wide Area Network. Compare with LAN, MAN
WAP Wireless Application Protocol. A new protocol that is supposed to provide more efficient internet access from wireless phone. See also WML
WAP W3C WAP - W3C Coordination Committee
WAR WLAN Access Router. Manages traffic into and out of a wireless LAN.
WARC World Administrative Radio Convention
WASP Wireless Application Service Provider
WASU Wireless Access Subscriber Unit
WATM Wireless ATM
WATS Wide Area Telephone Service
WAVE See 802.11p
WBMP Wireless Bit MaP. A WAP graphic format
WCMP Wireless Control Message Protocol. Protocol for reporting errors and performing loopback testing in WAP. Based on ICMP
WCTP Wireless Communications Transfer Protocol. An interface between internet applications and messaging service providers (e.g. paging carriers). Developed by See RXP
WDM Optical Wavelength Division Multiplexing
WDP Wireless Datagram Protocol. See WAP
WEMT CDMA Wireless Enhanced Messageing Teleservice
WEP Wired Equivalent Privacy. First security system for 802.11 WLAN. Has known security weaknesses in the algorithm and the use of fixed keys. WEP derives a 64 bit RC4 key from a 40 bit AP-specific key and a 24-bit IV that is unique to the session. Compare with WPA
WFQ Weighted Fair Queuing
WG Working Group
WGS-84 World Geodetic System 1984
WI Work Item
WID 3GPP WI Description.
WIF Wireless Interconnect Forum (managed by Telcordia)
WiFi IEEE 802.11b wireless LAN system
WIG WAP Interoperability Group
WIM WAP Identity Module
WiMax IEEE OFDM radio interface. In February, 2011, Andrew Seybold found average download speeds of about 6 Mbps and upload of about 2 Mbps in a Clear network system using 10 MHz of spectrum.
WIMS Wireless Multimedia Message Service
WIN Wireless Intelligent Network. Protocol with similar goals as IN, AIN and CAMEL
WIN Phase I Supports voice controlled services, incoming call screening and CNAP/CNAR
WIN Phase II Supports billing-related services, including Prepaid and Freephone (i.e. 1-800, including airtime)
WIN Phase III Supports location-based services, such as location sensitive billing and intelligent directory assistance
WIP WIN Implementation of PAS
WIPP Wireless Internet Protocol Partnership
WLA Optical Wavelength Adapter
WLAN Wireless LAN, of which the most popular is WiFi
WLL Wireless Local Loop. See FWA
WML Wireless Markup Language. An HTML-like page description and scripting language, that is an essential part of WAP. Compare with cHTML and XHTML
WMLSc WML Script
WNE Wireless Network Entity
WNO Wireless Network Operator. A carrier
WNP Wireless Number Portability. LNP for wireless phones
WNP Phase I The ability for a switch to route to a ported number in another switch
WNP Phase II The ability for a switch to allow numbers to be ported in or out of its number range
WNP Phase III The ability to support services such as short message service in a number portability environment
WP Working Party
WPA WiFi Protected Access. An enhanced version of WEP that does not rely on a static, shared key.
WPAN Wireless Personal Area Network. Standards are being defined by IEEE 802.15
WPG WAP WIreless Protocols Group
WPS Wireless Priority Service. See PACA, PS, NS/EP
Wr Interface between Proxy AAA and WLAN access network.
WRE Wireless Residential Extension - home base station
Ws Interface between Proxy AAA and Home system AAA.
WSDL Web Service Description Language
WSI Wireless Service Indication
WSP Wireless Session Protocol. See WAP
WTA Wireless Telephony Applications
WTAI WTA Interface
WTB US FCC Wireless Telecommunications Bureau
WTLS Wireless Transport Layer Security. See WAP
WTP Wireless Transaction Protocol. See WAP
WWAN Wireless WAN
www World-Wide Web
Wx Interface between AAA and HSS
WZ1 World Zone 1. An obsolete telephone numbering term for countries identified by country code 1 (USA, Canada and some Caribbean nations)


X.25 An ITU/CCITT defined general purpose packet switching protocol
X.500 The ISO directory protocol. See DAP, LDAP, DNS
xDSL Refers to all the DSL variants
XHTML Extensible HTML. A version of HTML defined by XML and designed to be extensible. This may also be the evolutionary path for cHTML and WML
XMAC Expected MAC
XML Extensible Markup Language. A meta-language that can be used to define languages like HTML and WML
XOR Exclusive OR. A boolean operation, often used in cryptography. The exclusive-or of two bits is 1 if they have the same value and 0 if they have different values. This operation has the nice property that no information is lost. For example, (A xor B) xor B = A and (A xor B) xor A = B. Try that on any other boolean operation!
XRES Expected response to authentication challenge. For AKA it is derived from RAND using f2. Compare with AUTHR
XUDT Extended UDT. Supports message segmentation


Z.300 An ITU-T series of specifications related to MML
ZBTSI Zero Byte Time Slot Interchange (TSI). Bits 2 through 193 of each DS1 frame are scrambled to minimize the possibility of an all-zero octet. If all zero octets are still found, a group of all-ones is substituted. Due to its complexity this method is not often used.
ZCS Zero Code Suppression. The seventh bit of an all-0 octet is replaced by a 1-bit. Only applicable to voice because there is no way to remove this one bit error.
ZigBee A 'cable replacement' radio technology. Somewhat a competitor to Bluetooth although it is designed more for M2M applications (home, business and inustrial automation). It claims to be cheaper and use less power. It uses unlicensed bands at 2.4 GHz, 915 MHz (US) or 868 MHz (Europe). Data speeds are 20–250 kbps depending on the frequency band used. The communications range is from 10 to 75 meters. Developed by the ZigBee Alliance and standardized as IEEE 802.15.4
ZRP Zone Routing Protocol. An internet routing protocol that focuses on routing updates within a zone.