Center for Wireless Telecommunications

0-9	Top

10 BaseT	The IEEE 802.3 specification for Ethernet over unshielded twisted pair (UTP); Basic Ethernet at 10 Mbit/sec.
100 BaseFX	100 Mbps Ethernet implementation over fiber.
100 BaseT	Fast Ethernet; Ethernet running at 100 Mbit/sec.
100 BaseTX	The IEEE 802.3u specification for Fast Ethernet over Category 5 (CAT5)unshielded twisted pair.
1000 Base-T	Ethernet running at 1,000 Mbit/sec
1G	First Generation. Refers to analog cellular systems.
1xEV-DOCDMA	1x Evolution - Data Only
1xEV-DVCDMA	1x Evolution - Data and Voice services
1XRTT	cdma2000 operating mode at basic chip rate (1.2288 Mcps)
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
3GPP	The Third Generation Partnership Project, set up to expedite the development of open, globally-accepted technical specifications for 3G services.
3G Services	Shorthand term for "third generation services." Generally applied to wideband mobile services.
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
3R	Reshaping, Retiming, Reamplifying (an optical signal). See 2R
3XRTT	cdma2000 operating mode at 3 times the basic chip rate of 1.2288 Mcps
802.11An	IEEE wireless Ethernet replacement technology in the ISM band. Runs at approximately 10 Mbps
802.15	See Bluetooth

A	Top

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
A8	GSM voice encryption algorithm. Used to generate Kc
AAA	Authentication, Authorization and Accounting entity
AAL	AAL Adaptation Layer
A-bis	Interface between BTS and BSC
ABR	Average bit rate
ABS	Alternate Billing Service
Absorption	In an antenna, the process within a poorly conducting material in which RF energy is absorbed and converted to heat energy.
AC	Authentication Center. Stores information for authenticating mobiles, and encrypting their voice and data transmissions
ACC	Analog Control Channel. See FSK
Access	The method, time, circuit, or facility used to enter the network.
Access Coordination	The design, ordering, installation, preservice testing, turn-up and maintenance on local access services.
Access Line	The circuit used to enter the communications network.
ACCOLC	Access Overload Class
Account Codes	Also known as Project Codes or Bill-Back Codes. Account Codes are additional digits dialed by the calling party that provides information about the call. Typically used by hourly professionals (accountants, lawyers, etc.) to track and bill clients, projects, etc.
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. 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
ACMSS7	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	Abbreviated Dialing
ADA	Advertising Agent. Provides information to a MS on the services provided by a 3G network
Address Mask	A 32-bit long mask used to select an IP address for subnet addressing. The mask selects the network portion of the IP address and one or more bits of the local LAN address.
Address Translation	The process of converting external addresses into standardized network addresses and vice versa. Facilities interconnection of multiple networks which each have their own address plan.
ADDS	Application Data Delivery Service. See SMS
ADPCM	Adaptive Differential PCM
ADS	Asynchronous Data Service
ADSL	(Asymmetric Digital Subscriber Loop) ADSL is a technology that allows data to be sent at rates as high as 6 Mbps through the conventional (analog, copper) telephone line, and is considered one of the most promising ways of connecting the "Information Superhighway" to the home. In collaboration with Aware, Inc. of Cambridge, Analog Devices has developed systems that support this standard.
AEG	Asian Expert Group. A WAP Working Group
AES	(1)Advanced Encryption Standard. 2)Audio Engineering Society
AFLT	Advanced Forward Link Trilateration. A geolocation technique that utilizes the mobile station¹s measured time of arrival of radio signals from the base stations (and, possibly, other terrestrial measurements)
AFSK	Audio FSK. Communication by changing frequencies in the audio band rather than RF. Used by MF, DTMF
AGPS	Network Assisted GPS. Land station assists mobile in acquiring its position
AH	(1)Authentication Header. 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
AIN	Advanced Intelligent Network. Telcordia version of IN
A-interface	Interface between the MSC and BS
Air interface	The radio communications between a mobile handset and the base station. AIS Stands for Alarm Indication Signal, usually all ones--F11111111. Also known as a Blue Alarm which signals that an upstream failure has occurred.
AJ	Anti-Jam; a communication signal that is designed to resist interference or jamming.
AK	Anonymity Key
AKA	Authentication and Key Agreement. GSM term
A-Key	The primary CAVE authentication key, used to generate SSD
Alarm	A real-time indication or a signal of an abnormal situation or event. Usually includes a Priority or Severity Code.
Alert	A command to a mobile to notify the user of an incoming call or message
ALI	Automatic Location Information. A database that contains information about the location of emergency callers
Alternate Access	A form of local access where the provider is not the LEC, but is authorized or permitted to provide such service.
Alternate Access Carriers	Local exchange carriers in direct competition with the RBOCs. Normally found only in the larger metropolitan areas. Examples are Teleport and Metropolitan Fiber Systems.
Alternate Mark Inversion (AMI)	A line code used for T-1 and E-1 lines that has a 12.5% ones density minimum, and the one conditions of the signal alternate between positive and negative polarity.
AM	Amplitude Modulation. The simplest carrier modulation technique where the RF carrier's envelope is modulated -- used today by broadcast band (BC) stations.
AMA	Automatic Message Accounting. See CDR
Amateur Service	A radio communications service that licensed operators with no pecuniary interest use for self-training, communications, and technical investigations.
AMI	Alternate Mark Inversion. A line code used for T-1 and E-1 lines that has a 12.5% ones density minimum, and the one conditions of the signal alternate between positive and negative polarity.
AMPS	Stands for Advanced Mobile Phone System, which is the most common type of First Generation analog cell phone network. Because analog phones are suited for voice rather than data communications, AMPS networks are rapidly being supplanted by digital wireless networks. Operates in the 800 MHz frequency band and uses FDMA technology.
AMR	Adaptive MultiRate voice coder. Used in GSM and UMTS
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
AND	Abbreviated Dialing Numbers
ANI	(1)Automatic Number Identification. Provision of charge number during a call to allow toll calls without operator intervention. (2)Access Network Identifier
ANI II	ANI Information Digits. Describes the type of phone being used to call (e.g. residential line or payphone)
ANMSS7	ISUP Answer Message
ANSI	American National Standards Institute. A United States-based organization which develops standards and defines interfaces for telecommunications.
ANSI-136	The North American digital mobile standard previously known as Interim Standard IS-136 and used in TDMA (previously called D-AMPS) systems.
ANSI-41	See TIA/EIA-41
Answer Supervision	The off-hook indication sent back to the originating end when the called station answers.
ANT	ADSL Network Termination
Antenna	Passive device required to transmit and receive electromagnetic radiation and convert it into electrical signals.
AOA	Angle of Arrival. A position identification technology that detects the direction of a signal received from a transmitter at only one point. In this system, the transmitter's location is determined from the receivers' antenna position and the AOA of the signals that are from the antennas.
AoC	Advice of Charge
AP	Application Part (of a protocol)
APCO	Association of Public Safety Communications Officials
APDU	Application PDU
API	Application Programming Interface
APLMN	Associated PLMN
APM	Application Transport
APMN	Associated PMN
ARCH	(1) Access Response Channel. WAP Architecture Committee. A WAP Working Group
Architecture	The specifications of a system and how its subcomponents interconnect, interact and cooperate. Architectures are often described in multiple levels of abstraction from low-level physical to higher-level logical application and end-user views.
Area of Service (AOS)	The geographical area supported by a communication service. For 800 numbers, if AOS is "CC", it is using Complex Call routing.
ARI	Automatic Room Identification (Hotel/Motel room number)
ARIB	Association of Radio Industries and Businesses. Responsible for standardization of telecommunications protocols in Japan
ARM	ARQ Response Mode
ARP	Authorized Receipt Point. The sole entity authorized to settle and exchange roamer charges and revenue for a carrier
ARP	Address Resolution Protocol under TCP/IP. Used to dynamically bind a high level IP address to a low-level physical hardware address. ARP is limited to a single physical network that supports hardware broadcasting.
ARPU	Average Revenue Per User
ARQ	Automatic Repeat Request
AS	Internet Application Server. Handles applications for a range of addresses (e.g. a telephone switch)
ASE	Application Service Element
ASIC	Application Specific Integrated Circuit. A computer chip that is customized for a special purpose application
ASK	Amplitude Shift Keying; a digital modulation of the RF carrier's envelope.
ASN.1	Abstract Syntax Notation 1. A formal, textual, representation of a protocol message set
ASP	AS Process
ASR	Automatic Speech Recognition
ASR	Access Service Request. A document (or data transaction) sent to the LEC to order the local access portion of a circuit.
ASTA	Areas of Service State (list)
Asymmetric communications	Two-way communications in which the volumes of traffic in each direction are significantly different. For example, TV on demand.
Asynchronous	Not Synchronous. A form of concurrent input and output communication transmission with no timing relationship between the two signals. Slower-speed asynchronous transmission requires start and stop bits to avoid a dependency on timing clocks (10 bits to send on 8-bit byte). (Contrast with Synchronous).
Asynchronous Transfer Mode Adaptation Layer (AAL )	A series of protocols enabling to be made compatible with virtually all of the commonly used standards for voice, data, image and video.
AT	(1)Access Tandem. A switch that can be used to reach a variety of IXC's. (2)Access Terminal
ATIS	Alliance for Telecommunications Industry Solutions. Parent organization for the T1 standards committees and many telecom industry groups, such as OBF
ATM	An international ISDN high-speed, high-volume, packet-switching transmission protocol standard. ATM uses short, uniform, 53-byte cells to divide data into efficient, manageable packets for ultrafast switching through a high-performance communications network. The 53-byte cells contain 5-byte destination address headers and 48 data bytes. ATM is the first packet-switched technology designed from the ground up to support integrated voice, video, and data communication applications. It is well-suited to high-speed WAN transmission bursts. ATM currently accommodates transmission speeds from 64 Kbps to 622 Mbps. ATM may support gigabit speeds in the future.
ATM / SONET / SDH	These three types of high-speed fiber-optic systems (ATM switch interface, SONET/SDH network) are being deployed now in the LAN/WAN environment to connect workstations and to transport high bit-rate services.
ATP	Access Transport Parameter (also Adenosine Tri-Phosphate)
Attenuation	A loss of signal strength in a lightwave, electrical or radio signal usually related to the distance the signal must travel (e.g. fiber optic transmission must be regenerated approx. every 30 miles). Fiber optic attenuation is caused by transparency of the fiber, bending the fiber at too small of a radius, nicks in the fiber, splices, poor fiber terminals, FOTs, etc. Electrical attenuation is caused by the resistance of the conductor, poor (corroded) connections, poor shielding, induction, RFI, etc. Radio signal attenuation may be due to atmospheric conditions, sun spots, antenna design / positioning, obstacles, etc.
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	The process of validating and identifying a caller as being a legitimate system user.
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
AUTN3	GPP AKA Network Authentication Token
Auto-correlation	A measure of the similarity between a signal and a time-shifted replica of itself; a special case of cross-correlation; The auto-correlation function is the theoretical basis of direct sequence spread spectrum.
Automatic Number Identification	Originating Number. (1) The number associated with the telephone station(s) from which switched calls are originated (or terminated).2) A software feature associated with Feature Group D (and optional on Feature Group B) circuits. ANI provides the originating local telephone number of the calling party. This information is transmitted as part of the digit stream in the signaling protocol, and included in the Call Detail Record for billing purposes. (3) ANI may also be used to refer to any phone number.
Automatic Ring Down (ARD)	A private line connecting a station instrument in one location to a station instrument in a distant location with automatic two-way signaling. The automatic two-way signaling used on these circuits causes the station instrument on one end of the circuit to ring when the station instrument on the other end goes off-hook. This circuit is sometimes called a "hot-line" because urgent communications are typically associated with this service. ARD circuits are commonly used in the financial industry. May also have one way signaling. Station "A" rings Station "B" when Station "A" goes off hook, but Station "B" cannot ring Station "A".
AV	Authentication Vector
Availability	The probability of attaining a specified level of performance and maintaining that level for a scheduled period of time.
AVC	Analog Voice Channel
AWGN	Additive White Gaussian Noise
AWI	Alert with Information; used to transmit data while alerting an MS

B	Top

B/I	Busy/Idle bit
Baby Bell	see RBOC
Back Lobe	In an antenna, a radiation lobe whose axis makes an angle of about 180 degrees with respect to the beam axis of the antenna.
Backbone	The part of the network used as the primary path for transporting traffic between network segments; usually, the high-speed transmission facilities.
Backhaul	In a WAN network, communications between a WAN port on a LAN and either a subscriber port on a service provider's network or another WAN port on a second LAN. Often, the backhaul links the user's facilities to the backbone.
BAF	Billing Automatic Message Accounting Format. The CDR/AMA format used by most US wireline telecom carriers
BAIC	Barring of All Incoming Calls
Bandwidth	The range of frequencies, expressed in hertz (Hz), that can pass over a given transmission channel. The bandwidth determines the rate at which information can be transmitted through the circuit. ALSO: The information capacity of a communications resource, usually measured in bits per second. Also see Narrowband, Wideband and Broadband.
BAOC	Barring of All Outgoing Calls
Barring	Refusal to allow certain types of calls
BATS	Broadcast Air-interface Transport Service used by TIA/EIA-136
BCCH	Broadcast Control Channel
BCD	Binary Coded Decimal. Digits 0-9 are encoded as 4 bit numbers (nibbles). See TBCD
BCE	Base Station Central Equipment. See BSC
BCH	Bose, Chaudhuri, and Hocquengham error detection and correction methodology
BCM	Basic Call Manager. See WIN
BCSM	Basic Call State Model. An IN concept
BDN	Barred Dialing Number
Beam	A portion of a satellite antenna's footprint on earth. A typical satellite footprint is divided into a large number of beams.
Beamwidth	In an antenna, the angular sector in degrees of the radiated power pattern at the half-power (3dB) point.
Bearer capability	A capability of a transport protocol (e.g. a maximum bit rate 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
Bent-pipe	A signal relay scheme in which a terrestrial-based signal is sent to a satellite, which then relays the signal back to Earth with minimal processing by the satellite.
BER	(1)Bit Error Rate. (2)Basic Encoding Rules. See ASN.1
BICC	Bearer Independent Call Control
BIC-Roam	Barring of Incoming Calls while Roaming
BID	A SID allocated for accounting purposes. BID's are allocated by Cibernet
BISDN	Broadband ISDN
Bit	A contraction of binary digit, it is the smallest unit of information in a binary (ones or zeroes) system.
Bit errors	Ideally no errors will be received over a connection; in practice, due to noise, other signals, etc. errors will occasionally occur, even on a fiber link. A bit error test checks the physical link to verify that the number of errors received over a test period is within design limits.
Bits per second (bps)	Rate at which bits are transmitted.
BLASS7	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). Developed by the Bluetooth Consortium and IEEE 802.15
BLV	Busy Line Verification
BMIBS	MSC and Interworking function
BNF	Backus-Naur Form. A precursor to ASN.1 and other meta-languages
BNS	Billed Number Screening
BOC	Bell Operating Company
BOIC	Barring of Outgoing International Calls
BOIC-exHC	BOIC except to HC
BP	Bit Position
Bps	Bits per second. A measure of the speed of a transmission link
BPSK	Binary Phase Shift Keying -- Digital DSB suppressed carrier modulation.
BR	Border Router. Connects a CN with peer networks
BRI	Basic Rate Interface (64 kbps)
Bridge	A Layer 2 (data link) device that passes data traffic between networks.
Broadband	A classification of the information capacity or bandwidth of a communication channel. Broadband is generally taken to mean bandwidth higher than 2 Mbps.
Broadcast	A signal transmitted to all user terminals in a service area, or the process.
Broadcast SMS	Short messages sent to multiple mobiles in multiple cells, requiring only one message per cell
Broadcasting satellite service (BSS)	A radio communications service in which signals transmitted or retransmitted by satellites are used for direct reception by the general public.
BS	Base Station (includes BTS and BSC
BSC	Base Station Controller. The 'brains' of a base station, controlling the radio equipment in the BTS
BSMC	Base Station Manufacturer Code
B-SMS	See Broadcast SMS
BSS	BS Subsystem
BSSMAP	GSM BSS MAP
BT	Burst Type
BTA	Basic Trading Area
BTS	Base Transceiver System (radio portion of BS
BTTC	Broadcast SMS
Bypass	A circuit that carries telephone signals from a subscriber to another point without the use of local telephone company circuits, by a CAP or CLEC.
byte	An 8 bit unit of data storage. See octet

C	Top

C/I	Carrier to Interference Ratio
C7	See CCS7
CA	Certificate Authority
CAC	Carrier Access Code. Identifies a long distance carrier. 101+CIC
CALEAUS	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
CANID	Current ANI
CAP	Competitive Access Provider, a service operator who provides alternate access to the user in place of the traditional local telephone company, often using wireless services.
Capacity	The average amount of traffic a circuit or port can handle. Capacity may be measured in terms of the number of VF channels or the aggregate data rate of the main signal.
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
CAS	Call Associated Signaling. See ISUP. Contrast with NCAS
CAT	Smart Card Application Toolkit
CAVETIA	Cellular Authentication and Voice Encryption Algorithm
CB	Cell Broadcast
CBC	CB Center
CBMI	CB Message Identifier
CBR	Constant Bit Rate
CBS	Cell Broadcast SMS
CC	(1)E.164 Country Code. (2)Call Control
CCA	Common Cryptographic Algorithm
CCF	Call Control Function (IN term)
CCITT	Precursor to ITU. See ITU-T and ITU-R
CCNR	Call Completion on No Reply. See CFNA
CCPN	Call Completion to a Ported Number. See LNP
CCR	(1)SS7 ISUP Continuity check request. (2)Class Conformance Requirement
CCS	Common Channel Signaling
CCS7	ITU-T version of SS7
CCSC	Cellular Carrier Specific Code (e.g. #123)
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. A way to increase channel capacity by using code sequences as traffic channels in a common radio channel. This technology was originally developed for military use over 30 years ago. Also -- A digital signal multiplexing technique where each signal is split into many chips of data, each of which is tagged with a particular code. During transmission, the chips are spread over a band of frequencies, then reassembled at the receiving end. This technique permits many different signals to be co-located in the same frequency band.
CDMA One (IS-95)	A narrowband, second generation digital air interface technology developed by the US firm Qualcomm.
CDMA2000	3G evolved from CDMA One. The CDMA community's proposal for a system standard for 3G services.
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	Call Detail Record
CDRP	Call Detail Rating Point
CDVCC	Coded Digital Verification Color Code
CEG	Carrier Expert Group. A WAP Working Group
Cell	The basic geographical unit of a cellular communications system. Service coverage of a given area is based on an interlocking network of cells, each with a radio base station (transmitter/receiver) at its center. The size of each cell is determined by the terrain and forecasted number of users.
Cell Splitting	A method of increasing capacity of a wireless system by reducing the size of the cell (local area near a transmitter).
Cellular	A radio concept that allows the multiplication of capacity by using many low-power cells to cover an area, reusing frequencies as much as possible
CELP	Code Excited Linear Prediction
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)
CGB	SS7 ISUP Circuit group blocking
CGBA	SS7 ISUP CGB acknowledgement
CGI	Common Gateway Interface
CGL	Calling Geodetic Location. The position of a mobile phone, as transmitted through various signaling protocols
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
CH or channel	Channel, usually referring to one 300 Hz 3,300 kHz (VF) bandwidth voice circuit.
CHAP	Challenge Handshake Authentication Protocol
Chip	The time it takes to transmit a bit or single symbol of a PN code.
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
CIBER	Cellular Intercarrier Billing Exchange Record. Format used for exchange of wireless billing records. Maintained by Cibernet Corp
Cibernet	A subsidiary of the CTIA responsible for facilitating billing aspects of roaming
CIC	Carrier Identification Code. See CAC
Ciphertext	Encrypted data. Compare with Plaintext
CIR	(1)Synonym for C/I. (2)Committed Information Rate. Bandwidth associated with a frame relay PVC
Circuit	Physical connection of channels, conductors, and equipment required to provide a complete communications pathway.
Circuit switching	The basis of telephone call handling, with a circuit connection being set up between caller and called party. This connection is held open for the duration of the call, even when no information (voice, data, images or video) is being transmitted. The alternative is packet switching.
Circuit-switched data	Data transmitted over a dedicated (although usually virtual) channel. The destination address is implicitly defined by the (virtual) circuit that is selected
Circular Polarization	In an antenna, where the tip of the field vector, as viewed in the direction of propagation, rotates either clockwise (right hand) or counterclockwise (left hand).
CITEL	Commission InterAmericanna de Telecommunications Association. A Latin American telecommunications association
CK	Cipher Key
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 Local Exchange Carrier. A service operator who provides alternate telephone and/or data services to the user in place of the traditional local telephone company, often using wireless services.
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	Connection Management
CMAC	Control Mobile Attenuation Code
CMEA	Cellular MEA. Based on CAVE
CMIP	Common Management Information Protocol
CMOS	Complementary Metallic Oxide Semiconductor.
CMRS	Commercial Mobile Radio Service
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
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 Reduction Factor (CIRF)	A key factor used to design a cellular system to avoid co-channel interference.
Code	A digital bit stream with noise-like characteristics.
Codec	Abbreviation of encoder/decoder; refers to a device that digitizes analog signals, for example a video IP Codec takes an analog video signal and outputs digital IP packets.
COFDM	Code OFDMA
COFETEL	Comision Federal de Telecomunicaciones de Mexico
Co-linear Array	In an antenna, a linear array of dipoles with their axes lying in a straight line.
Common Carrier	A government-regulated company responsible for the provision of telecommunications services in a given territory, providing users (at a tariffed cost) with access to communications. Common carriers have a requirement to provide this service to users on demand in their territory.
CONS	Connection-Oriented Network Service
Continuous Time Oversampling	A technique Developed by Analog Devices that simplifies the job of synchronizing data generated from disparate sampling rates. The technique resamples and synchronizes modem, audio, and video data as needed, and it eliminates the substrate noise and feedthrough problems.
Control Channel	A cellular or PCS channel that broadcasts information about a cell to mobiles that are not currently in a call
Convergence	In the context of mobile communications, convergence means many things. There is convergence of industry sectors, including telecommunications, information, media and entertainment; convergence of technologies, for example, of fixed and mobile communications and of telecommunications and computing; and there is convergence between mobile communications standard themselves.
CORBA	Common Object Request Broker Architecture
CORD	Cellular Operations Record Distribution
Core network	The physical network infrastructure to which the radio access network is connected in a mobile network.
Correlator	The SS receiver component that demodulates a Spread Spectrum signal; a device that measures the similarity of an incoming signal and a stored reference code.
CoS	Class of Service. Method of managing traffic by grouping similar types (e.g. voice, video, email)
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
CPG	SS7 ISUP Call ProGress Message
CPN	See CgPN
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. (2)Core Quality of Service Manager
CR	Change Request
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	Customer Resource Management
Cross Polarization	In an antenna, polarization orthogonal to a specified reference.
Cross-correlation	A measure of the similarity of two different signals.
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-1IN	CS (Capability Set) 1
CS-2IN	Capability Set 2
CSA	Canadian Standards Association
CS-ACELP	Conjugate Structure ACELP
CSC	Customer Service Center
CSD	Circuit switched data. Compare with Packet data
CSFP	Coded Superframe Phase
CSI	CAMEL Subscription Information
CSIN	Capability Set
CSMA	Carrier Sense Multiple Access
CSMA/CD	CSMA with CD. Ethernet devices use this to minimize collisions by checking the line before sending
CSS	Cascading Style Sheets. See HTML
CSU	Channel Service Unit. Unit that interfaces between the telephone company and a private network
CSU	Channel service unit, a terminating device normally required at the customer premises for a T1 leased line connection.
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

D	Top

D Digit	The fourth digit of an NANP phone number. Currently restricted to the values 2-9 to allow 7 digit dialing
DACS	See DCS
D-AMPS	Digital AMPS (IS-54 and IS-136 TDMA
D-AMPS (IS-136)	Digital AMPS, the digital wireless standard widely used throughout the Americas, Asia Pacific and other areas. D-AMPS services can be introduced in the 800 MHz and 1900 MHz frequency bands. Uses a TDMA-based air interface.
Data Link Layer	Layer 2 of the OSI model; this layer takes the physical (Layer 1) transmission facility and transforms it into a channel that satisfies the addressing, error detection and flow requirements.
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	Decibel, Isotropic; decibel referenced to the gain of a theoretical isotropic radiator.
dBm	Decibel, Milliwatt; decibel referenced to one milliwatt into 50 ohms (typical for RF systems).
DBS	Direct (to home) Broadcast (Satellite) System.
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)
DCN	Data Communications Network.
DCS	(1)Data Coding Scheme. (2)Digital Cross-Connect System
DECT	Digital European Cordless Telecommunications - a standard issued by ETSI for local area digital cordless communications.
DES	Data Encryption Standard. A commonly used encryption method, usually used with 56 bit keys
De-spreading	The process used by a correlator to recover narrowband information from a spread spectrum signal.
DF	(1)UIM Dedicated File. Compare with EF and MF
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
Diffie-Hellman	A secure key exchange mechanism
Diffraction Loss	The loss between two antennas caused by the scattering of energy from a knife-edged or rounded obstruction in the path between them.
Diffserv	Differentiated Services. Different QoS for different types of traffic (e.g. voice, video, email)
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
Digital Cellular Telephone	A generation of car telephones served by a cluster of receiver-transmitter cell site receiver/transmitters; as the car travels, a telephone call is activated by transferring it from cell site to cell site.
Digital Network	A second generation cell phone network employing digital technology to convert the sounds of users' voices into streams of bits that are then used to modulate the wireless signals. Digital networks can also be used for data communications. These networks came into use in the 1990s.
Dipole Antenna	Any one of a class of antennas producing a pattern with a node or zero level at each end.
Directive Gain	In a given direction, 4pi times ratio of the radiation intensity in that direction to the total power radiated by the antenna.
Director Element	In an antenna, a parasitic element forward of the driven element intended to increase the directivity of the antenna in the forward direction.
Disconnection	The end of a call. Not to be confused with termination of a call or the release of a trunk
Distributed Control Systems, or DCS	An industrial measurement and control system routinely seen in factories and treatment plants consisting of a central host or master (usually called a master station, master terminal unit or MTU); one or more field data gathering and control units; and a collection of standard and/or custom software used to monitor and control field data elements. Unlike similar SCADA systems, the field data gathering or control units are usually located within a more confined area. Communications may be via a local area network (LAN), and will normally be reliable and high speed. A DCS system usually employs significant amounts of closed loop control.
Diversity	Sharing a signal characteristic to allow more users in the same frequency band.
DLCI	Data Link Connection 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
DMT	Discrete Multi-Tone line code being proposed for VDSL. Compare with QAM/CAP
DN	Directory Number. The number dialed to terminate a call to a phone
DNIC	Data network identification code
DNS	Internet Domain Name System. See RFC 1035
DOC	US Department of Commerce
DOI	Domain of Interpretation
Donor Switch	The switch from which a number has been ported. See LNP
Downlink	A radio link from a satellite to a receiving site on earth or in an aircraft.
DP	WIN/CAMEL Detection Point
DPC	(1)Destination Point Code for an SS7 message. (2)Downlink Power Control
DPCCH	Dedicated Physical Control Channel
DPCH	Dedicated Physical Channel
DPDCH	Dedicated Physical Data Channel
DPSK	Differential Phase Shift Keying -- a simplified BPSK where only data transitions are transmitted.
DQPSK	Differential Quadrature PSK
DRAC	Dynamic Resource Allocation Control
DRNC	Drift Radio Network Controller
DRNS	Drift RNS
DS	Direct Spread. See CDMA
DS0	Digital Signal Level 0. A 64 kbps digital link used to carry voice or signaling traffic. In ANSI networks, 8 kbps is usually reserved for in-band signaling, reducing the bandwidth to 56 kbps
DS1	Digital Signal Level 1. A 1.5 Mbps signaling link carrying 24 DS0 channels
DS-1	Digital Signal 1, a serial digital signal transmission format in which 24 duplex voice circuits are time division multiplexed into one 1.544 Mbps Tl digital circuit. May also be expressed as T1.
DS-3	Digital Signal 3, 44.7 Mbps or equivalent to 672 duplex voice circuits or 28 DS-1 signals.
DS-CDMA	Direct Sequence CDMA
DSCH	Downlink Shared Channel
DSF	Dispersion Shifted Fiber
DSI	Digital Speech Interpolation
DSL	Digital subscriber line; a technology to send high speed data over existing copper telephone lines.
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
DSS-1	Digital Subscriber Signaling System No. 1
DSU	Digital Service Unit
DSX-1	Digital Signal Interface 1, the standard levels, mask, etc. that specify the format of the signal at an interface point.
DTC	Digital Traffic Channel
DTCH	Dedicated Traffic Channel
DTD	Document Type Definition. An XML grammar specification
DTE	Data Terminal Equipment
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
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
Duplex	A circuit or device that permit s transmission in two directions at once (receiving and transmitting).
Duplex Operation	Operating method in which transmission is possible simultaneously in both directions of a telecommunications channel.
DVCC	Digital Verification Color Code
DWDM	Dense Wave Division Multiplexing

E	Top

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 E1.64 number to allow routing through SS7 networks. Unfortunately, this mapping does not work in North America
E1	Specialized circuit developed in Europe for transmission of digital signals over the telephone network at 2.048 Mbps or equivalent to 30 duplex voice circuits plus two data channels. Also, E2 at 8 Mbps, E3 at 34 Mbps and E4 at140 Mbps.
E911	Enhanced 9-1-1 service. Provides the identity and the approximate location of the calling phone
EACC	Emergency Area Congestion Control
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
EBNF	Extended BNF. Used to define XML, for example.
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
EDACC	DMA Error Detection and Correction coding. See FEC
EDGE: Enhanced Data Rates for Global Evolution	an enhanced radio modulation technique for GSM and TDMA (ANSI-136) networks that expands radio timeslots to 48 kbit/s. When combined with GPRS, it gives a maximum bandwidth of 384 kbit/s per subscriber in the U.S.
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
EEPROM	Electronically Erasable Programmable Read Only Memory.
EESN	Expanded ESN
EF	UIM Elementary File. Compare with DF and MF
EF&I	Engineer, Furnish and Install. Additional services provided to customers, usually at an additional charge.
EFI	External Functionality Interface
EFR	Enhanced Full Rate. GSM voice coder
E-GGSN	Enhanced GGSN
E-GPRS	Enhanced GPRS, another term for EDGE.
EGPRS-136	GPRS adapted for use in TIA/EIA-136 networks
EHFC	Extended Hyperframe Counter
EIA	Electronics Industry Association
EIA/TIA-553	Analog 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
electric field	In an antenna, the force field associated with the current distribution of an antenna element, tangential to the element and expressed in volts per meter. It is mutually perpendicular to the magnetic field.
EMI	Exchange Message Interface. A LEC billing record format. Compare with
EMR	Exchange Message Record. A LEC billing record format. Compare with EMI. Contrast with BAF and CIBER
EO	End Office
EOM	End Of Message
E-OTD	Enhanced Observed Time Difference. A positioning technology for wireless phones. Compare with AOA, TOA, TDOA
EP SCP	ETSI Project Smart Card Platform
EPE	Enhanced Privacy and Encryption. A North American TDMA architecture that secures voice, messages, and data through encryption
EPOC	The operating system for mobile multimedia being developed by Symbian.
EPROM	Electronically Programmable Read Only Memory.
Erlang	Measure of traffic load. Calculated as rate at which calls arrive divided by the rate at which they are completed
Erlang BA	traffic model used to engineer resource groups when blockage is low, and the average holding time is known
Erlang CA	traffic model commonly used for provisioning data circuits
ERMES	European Radio Messaging System
ERP	Effective Radiated Power
ERROR RESULT	Message sent to unsuccessfully end TCAP transaction
ESAE	Enhanced Subscriber Authentication. A long term replacement to the TIA CAVE algorithm
ESC	Emergency Services Call
ESME	(1)Emergency Services Message Entity. Entity that receives E911 messages from an MSC (e.g. ALI or S/R). (2)External SME
ESMR	Enhanced SMR. Allows 'cellular' service as well as traditional SMR services
ESN	Electronic Serial Number. 32 bit identifier of an AMPS mobile
ESNE	Emergency Services Network Entity. Entity that is connected to an E911 trunk from an MSC (e.g. S/R or PSAP
ESNX	See EESN
ESP	(1)Emergency Service Provider. (2)Enhanced Subscriber Privacy. New and stronger TIA voice encryption algorithms
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
ETACS	Extended TACS
Ethernet	A baseband LAN specification to network computers at 10 Mbps using CSMA/CD to run over coaxial cable. Referenced by IEEE standard 802.3.
ETR	ETSI Technical Report
ETS	European Telecommunication Standard
ETSI	European Telecommunications Standards Institute. A body formed by the European Commission in 1998, which included vendors and operators. ETSI's purpose is to define standards that will enable the European market (particularly for its citizens) for telecommunications to function as a single market.
EVRC	Enhanced Variable Rate Voice Coder. An IS-95 voice coder for use on CDMA systems
Extranet	A private network that uses Internet software and standards with limited external access, typically for an organization's suppliers and customers.
Extremely High Frequency (EHF)	A signal in the frequency range of from 30 to 300 GHz.
Extremely Low Frequency (ELF)	A signal in the frequency in the range from 30 to 300 kHz.

F	Top

FA	(1)Foreign Agent. (2)Flexible Alerting. A badly named feature that is really an extension phone service for wireless calls
FACCHFast	Associated Control Channel
Fading	An effect caused during the transmission of radio signals due to the non-uniform nature of the atmosphere. Signals may fade up or down occasionally over time and sufficient margin is required to maintain a reliable connection.
FAQ	Frequently Asked Questions
F-BCCHFast	Broadcast Control Channel
FBIUS	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	Federal Communications Commission. The US government agency regulating telecommunications; the FCC is also responsible for establishing rules, licensing or authorizing all wireless transmitters.
FCCUS	Federal Communications Commission
FCI	Forward Call Indicator. Used to indicate whether a number portability query has occurred for this call (to prevent looping)
FCS	Frame Check Sequence
FDCCH	Forward DCCH
FDD	Frequency Division Duplex
FDDI	Fiber Distributed Data Interface
FDM	Frequency Division Multiplex. See FDMA
FDMA	Stands for Frequency Division Multiple Access. This multiple access technique allows many cell phone users to communicate with one base station by assigning each user a different frequency channel. An AMPS network, for example, has 832 channels spaced about 30 Khz apart. In digital networks, FDMA is used in conjunction with CDMA or TDMA.
FDN	Fixed Dialing Number
FDTC	Forward DTC
FE	Functional Entity. A logical element of a network. Not necessarily realized as a physically distinct device
FEC	Forward Error Correction. A technique used to improve the error performance of a digital radio by adding redundancy into the transmitted digital signal.
FEC	Forward Error Correction (coding / decoding technique).
Feeder Link	A radio link between an earth station and a satellite, conveying information for a space radio communications service other than fixed satellite service. In the broadcasting-satellite service, all feeder links are uplinks (from the earth to the satellite), but in the mobile-satellite service, feeder links can be both uplinks and downlinks.
FE-NTS	Feature Enhanced NTS
FER	Frame Error Rate
FEXT	Far End CrossTalk
FFT	Fast Fourier Transform
FHMA	Frequency Hopping Multiple Access
FHSS	Frequency Hopping Spread Spectrum.
FIFO	First in, first out. A queuing methodology similar to lining up for a bank teller. Compare with LIFO
FIPS	US Federal Information Processing System
First Generation	Refers to early analog cell phone systems, those developed in the 1980s but still in use today.
Fixed Radio Access (FRA)	A telephone system where subscribers are connected to the Public Switched Telephone Network using radio signals rather than copper wire for part or all of the connection between the subscriber and the switch. Includes cordless access systems, proprietary fixed radio access and fixed cellular systems. Synonymous with Radio in the Loop and Wireless Local Loop Systems.
Fixed service	A point-to-point radio communications service between specific fixed stations on the earth.
Fixed wireless network	Also called fixed cellular network. This apparent contradiction in terms signifies a cellular network that is set up to support fixed rather than mobile subscribers. Increasingly being used as a fast and economic way to roll out modern telephone services, since it avoids the need for fixed wires.
Fixed-satellite service (FSS)	A radio communication service between earth stations at given fixed positions via one or more satellites.
FLEXA	Motorola one-way paging protocol that runs at 1600, 3200 or 6400 bps. Compare with POCSAG
FM	Frequency Modulation; modulation of the RF carrier frequency-another very simple modulation, used today in the FM band.
FOCC	Forward Control Channel. Used to send signaling messages from a base station to one or multiple mobiles
FPLMTS	Future Public Land Mobile Telecommunications Systems. Now IMT-2000
FR	Full Rate (e.g. for a voice coder). Compare with FR
Fractional	A digital signal with a capacity lower than T1 or E1; usually, fractional signals may have serial interfaces, such as V.35, and data rates between 64 kbps and 2 MB.
Frame Relay	High performance WAN interface for packet-switching networks used to handle bursty communications with rapidly changing bandwidth needs; implemented over T1, DS-3 and OC-3 interfaces.
Free-Space Path Loss	In an antenna, the loss between two isotropic radiators in free space resulting from the decrease in power density with the square of the separation distance.
Frequency	The number of cycles per second at which a current alternates, usually expressed in Hertz (Hz).
Frequency allocation	A band of radio frequencies identified by an upper and lower frequency limit earmarked for use by one or more of the 38 terrestrial and space radio communications services defined by the International Telecommunication Union under specified conditions.
Frequency allotment	The designation of portions of an allocated frequency band to individual countries or geographical areas for a particular radio communication service; for a satellite service, specific orbital positions may also be allotted to individual countries.
Frequency assignment	Authorization given by a nation's government for a station or an operator in that country to use a specific radio frequency channel under specified conditions.
Frequency reuse factor (K)	A number based on frequency reuse to determine how many channels per cell.
FSK	Frequency Shift Keying; a digital binary modulation of the RF carrier frequency.
FSN	Frame Sequence Number
FTAM	File Transfer, Access and Management
FTN	Forward-To Number
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	Top

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 defines this. Related to T1.628
Gain, dB	A ratio of output divided by input, expressed in decibels. In antennas, the ratio of the radiation intensity, in a given direction, to the radiation intensity that would be obtained if the power accepted by the antenna were radiated equally in all directions (isotropically).
Gain, dBd	Antenna gain, expressed in decibels referenced to a half wave dipole.
Gain, dBi	Antenna gain, expressed in decibels referenced to a theoretical isotropic radiator.
Gain, dBic	Antenna gain, expressed in decibels referenced to a theoretical isotropic radiator that is circularly polarized.
GAIT	GSM/ANSI-41 Interoperability Trial
GAP	SS7 ISUP Generic Address Parameter
Gateway MSC	An MSC designed to receive wireless calls from the PSTN
Gbps	Gigabits per second. The transmission of ten million bits of information per second, or 1,000 Mbps; also Gigabit Ethernet, 1000 BaseT.
GDP	ISUP Generic Digits Parameter
GECO	Global Emergency Call Origination
GEO	Geostationary Orbit (for a satellite)
Geostationary satellite orbit (GSO)	A circular orbit approximately 35,900 km above the earth, in the plane of the earth's equator, in which a satellite revolves around the earth in the same time that the earth rotates on its axis; thus the satellite appears approximately stationary over one point on the earth.
GERAN	GSM EDGE RAN
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 GPRS Service Node
GHOST	GSM Hosted Short Message Teleservice. Allows TIA/EIA-136 messages to be delivered to a GSM MS
GHz	Gigahertz. The microwave frequency range, a signal frequency equivalent to one billion cycles per second.
Giga	Prefix to indicate one billion (e.g. Giga-bit). Abbreviated G
Gigabit	Ten million bits of information.
GII	Global Information Infrastructure
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
GMM	GPRS Mobility Management Protocol
GMSC	See MSC-G
GMSK	Gaussian MSK
GPRS: General Packet Radio Service	A planned improvement for GSM networks that implements packet switching for data communications. Instead of sending data on dedicated circuits, a packet-switching network divides the information into packets and transmits them on any of the network's available channels.
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
GSL	Global Service Logic
GSM: Global System for Mobile Communications	The European standard for digital networks, which guarantees the compatibility of wireless devices-so that a German cell phone can be used on a French network, for example. Uses TDMA technology and can be implemented in 900 MHz, 1800 MHz or 1900 MHz frequency bands.
GsmSCF	GSM SCF for CAMEL
GsmSRF	GSM SRF for CAMEL
GSN	GPRS support node
GSTN	General Switched Telephone Network. Synonym for PSTN
GT	Global Title. A non-native SS7 address based on E.164 DNA�s, E.212 IMSI, etc.
GTA	GT Address
GTAI	SS7 SCCP GT Address Indicator
GTT	(1)Global Title Translation. A method of routing in SS7 networks based on an global titles and not Point Codes. (2)Global Text Telephony
GUG	GVNS User Group
GUTS	General UDP Transport Service
GVNS	Global Virtual Network Service

H	Top

HA	MIP Home Agent
HAAA	Home AAA
HAC	HA Challenge
Half-Duplex Operation	Operating method in which transmission is possible in both directions, but only in one direction at a time.
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 HANDMREQ
Handoff	A frequency channel will be changed to a new frequency channel as the vehicle moves from one cell to another without the user's intervention.
HC	Home Country
HCM	Handset Configuration Management. See IOTA
HDLC	High Level Data Link Control
HDML	Handheld Markup Language
HE	Home Environment
Hertz	Unit of frequency equal to one cycle per second.
HFC	(1)HF Counter. (2)Hybrid Fiber-Coax
HF	Hyperframe
High Frequency (HF)	A signal in the frequency range of from 3 to 30 MHz.
HIPPI	High-Performance Parallel Interface
HLPI	Higher Layer Protocol Identifier
HLR	Home Location Register
HMAC	Hashed MAC
Home MSC	The MSC to which the PSTN routes based on an MDN
HomeRF	Promoters of the SWAP protocol for in-home wireless networking
Hop	Refers to a single point-to-point radio link, generally including two radio terminals and antenna systems.
Horizontal Polarization	In an antenna, a linearly polarized electric field vector whose direction is horizontal relative to ground or some arbitrary coordinate system.
HPC	High Probability of Completion
HPLMN	Home PLMN
HR	Half Rate (e.g. for a voice coder). Compare with FR
HRFWG	HomeRF WG
HSCSD	High Speed Circuit Switched Data. GSM enhanced to allow up to 57.6 kbps data rates
HTML	Hypertext Markup Language
HTTP	Hypertext Transfer Protocol (RFC 2068)
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	Top

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
IAP	Intercept Access Point. A point within the telecommunications network that provides voice or data for CALEA interception to a DF
Ic	see IXC
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. Motorola¹s proprietary system for E-SMR, used by Nextel and others. Based on GSM
IDL	Interface Description Language
IE	Information Element
IEC	(1)See IXC. (2)Internet Engineering Consortium. (3)International Electrotechnical Commission
IEEE	Institute of Electrical and Electronic Engineers
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
IIF	Interworking and Interoperability Function
IK	Integrity Key
IKE	Internet Key Exchange
ILEC	Incumbent local exchange carrier; the local telephone company who generally owns all the local loop installed copper.
IMEI	International Mobile Equipment Identity
IMGI	International Mobile Group Identity
IMM	See IM
IMode	Japanese (NTT DoCoMo) wireless internet access system. See cHTML
IMSI	International Mobile Subscriber Identity. Formerly called International Mobile Station Identity. Based on the ITU-T E.212 numbering plan
IMT-2000	The term used by the International Telecommunications Union for the specification for the projected third-generation wireless services. Formerly referred to as FPLMTS, Future Public Land-Mobile Telephone Systems.
IMUI	International Mobile User Identity
INAP	IN AP. The IN messaging protocol
INC	Industry Numbering Committee (for the NANP
INM	Integrated Network Management
INN	Internal Network Number
Intelligent Network (IN)	A capability in the public telecom network environment that allows new services such as Freephone or televoting to be developed quickly and introduced on any scale, from a local trail to network-wide. Also implies a well-developed network infrastructure.
Interface	A connection between two network elements. Compare with Protocol
Internet	The name given to the worldwide collection of networks and gateways using the TCP/IP protocol that functions as a single virtual network.
Internetworking	A term used for the products, procedures and technologies developed in order to connect networks together.
Intranet	A private network for an organization that uses Internet software and standards.
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
IOTA	IP-based Over-the-Air configuration management
IP	Internet protocol. An OSI model Layer 3 (network) format with addressing information and some control information for routing packet traffic on wide networks, such as the Internet. Documented in RFC 791.
IP Address	A number with 4 parts separated by dots: e.g. 101.113.259.002. Every computer on the Internet has its own unique IP address.
IPCP	IP Control Protocol
IPDR	Internet Protocol Detail Record. An internet oriented record for carrying charging details for services. Compare with CIBER, BAF, TAP, EMI
IPLMN	Interrogating PLMN
IP-M	IP Multicast
IpoA	IP over ATM
IPR	Intellectual Property Rights (e.g. patents)
IPSEC	IP Security
IR	(1)Infra-Red. (2)Intelligent Roaming
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	International Roaming Experts Group. A GSM organization
IRM	International Roaming MIN. A mobile subscription identifier beginning with the digit 0 or 1 to avoid conflict with NANP MINs
IS-124	Wireless call detail and billing record format for online transfer
IS-136	See TDMA (ANSI-136).
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-CIS-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-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 Center
ISDN	Integrated Services Digital Network. A digital public telecommunications network, in which multiple services (voice, data, images and video) can be provided via standard terminal interfaces. Offers two times 68 kbps over the landline network.
ISDN-UP	See ISUP
ISI	Inter-Symbol Interference
ISM	Industrial, Scientific, Medical frequency band (2.4-2.5 GHz). Available around the world for unlicensed applications, generally using low power and short distances
ISMA	Interference Sense Multiple Access
ISO	International Standards Organization. A worldwide federation of national standards bodies which have united to develop internationally accepted quality standards so that customers and manufacturers have a system in place that provides a known quality, for example, ISO 9001.
Isotropic Radiator	A hypothetical, lossless antenna having equal radiation intensity in all directions; used as a zero-dB gain reference in pattern measurements or directivity calculations.
ISP	Internet service provider; a company selling Internet access and gateway services to individuals or organizations by providing an interface to the Internet backbone.
IS-TIA	Interim Standard
ISUP	ISDN User Part. SS7 signaling between switches
ITAR	US International Traffic in Arms Regulations
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
ITS	Intelligent Transportation System ("Smart Highways")
ITU	International Telecommunications Union. Based in Geneva, the ITU is an organization of the UN that oversees cellular standards around the world.
ITU-R	ITU - Radio Communications Division
ITU-T	ITU - Telecommunications Division
IVR	Interactive Voice Response
IVRU	IVR Unit
IWF	Inter-working Function. Used for wireless data interworking between digital mode data and analog (e.g. modems)
IXC	Interexchange carrier; long distance telephone companies, for example AT&T, MCI and Sprint, that provide service between regions, generally interconnecting local telephone exchanges.

J	Top

JDC	Japanese Digital Cellular
JIP	ISUP Jurisdiction Information Parameter
J-STD-025	LAES standard
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
J-STD-Joint	ATIS-T1/TIA standard
JTACS	Japanese TACS
JTC	Joint Technical Committee (e.g. with members of more than one SDO

K	Top

k	The Constraint Length of a convolutional encoder or Viterbi decoder.
Kbps	kilobits per second
Kbps	Kilobits per second, a data rate equal to 1,000 bits per second.
Kc	GSM cipher key. Used for voice encryption
KG	Key Generator
Ki	GSM subscriber authentication key
Kilo	Prefix to indicate one thousand (e.g. kilo-bit). Abbreviated k
KSG	Keystream Generators
KSI	Key Set Identifier

L	Top

L1	Layer 1
L2	Layer 2
L3	Layer 3
LAC	Link Access Control
LAES	Lawfully Authorized Electronic Surveillance. See CALEA
LAI	Location Area Identity
LAK	Local Authentication Key
Land Mobile Station	A mobile station in the land-mobile service capable of surface movement within the geographical limits of a country or continent.
Land-Mobile Service	A mobile service between base stations and land-mobile stations, or between land-mobile stations.
Land-Mobile-Satellite Service	A mobile satellite service in which mobile earth stations are located on land.
LAP	Link Access Protocol
LAPB	Link Access Protocol, Balanced
LAPD	Link Access Protocol for the ISDN D Channel
Last Mile	The access portion of a network that extends the backbone to the end-user or customer.
LATA	Local Access and Transport Area. US local telephone service area
LB	Letter Ballot
LBS	Location Based Services
LC	SGSM Location Services
LCP	Link Control Protocol
LDT	Location Determination Technology
LEA	Law Enforcement Agency
Leakage	Inability to bill for a service
Leased line	Exclusive WAN connection rented from a telco; also called a private line.
LEC	Local Exchange Carrier (wireline carrier for local calls). Also see ILEC and CLEC
LE-LAN	License exempt LAN; unlicensed wireless regulation established by Industry Canada (IC) that matches the UNII band in the USA.
LEO	Low Earth Orbit
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
LIFO	Last in, first out. A queuing methodology similar to stacking dishes. Compare with FIFO
LIR	Location Identification Restriction. Prevents the location of a mobile phone from being revealed (with legal exceptions for E911, etc.)
LMDS	Local Multipoint Distribution Service
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 when changing carriers within the same geographical region
LNPWG	Local Number Portability Working Group of NANC
Local Area Network (LAN)	A series of connected workstations and computers that a re-linked in a limited geographical are a (e.g., office, building, and/or campus). LANs are usually low-cost, high-bandwidth networks which connect many nodes using Ethernet.
Local Exchange	Exchange in which subscribers' lines terminate, having access to other exchanges and to national trunk networks. Also, central office (CO). A local exchange carrier (LEC) is a common carrier that operates local exchanges in a given geographical area. (See ILEC and RBOC).
Local Loop	Telephone wires and other facilities that link local subscribers to the local telephone company's central office.
Long Haul	Voice, data or video transmission over unlimited distances.
LOS	Line of Sight. Always desirable for radio communications, and usually necessary for optical communications
Low earth orbit (LEO)	Any orbit around the earth substantially below the geostationary satellite orbit, generally below the geostationary satellite orbit, generally within several hundred km above the earth's surface and usually inclined to the equatorial plane.
Low Frequency (LF)	A signal in the frequency range of from 300 to 3000 kHz.
LPC	Linear Predictive Coding
LPDE	Local PDE
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
LSPI	Proposed SS7 ISUP Local Service Provider Identification
LT	Line Termination
LUDT	Long UDT. Supports messages up to 3 kilobytes in length
LYNX	Western Multiplex' spread spectrum T1/E1 and unlicensed DS-3 radio trade name.

M	Top

M	Mandatory (e.g. for a parameter)
M3UA	SS7 MTP3 User Adaptation Layer
MABEL	Major Account Billing Exchange Logistical Record. Defined by Cibernet to facilitate centralized billing for large account customers
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 neighboring base stations to determine which to handoff to
MAP	Mobile AP. Protocol that interconnects wireless telephone systems. See GSM and TIA/EIA-41
Mbps	Megabits per second is the transmission of one million bits of information per second.
MC	(1)Short Message Center. (2)Multi-carrier
MCC	E.212 Mobile Country Code
MCI	Malicious Call Identification
MCID	See MCI
Mcps	Million Chips-per-second. See CDMA
MD5	Message Digest 5
MD-IS	Mobile Data - Intermediate System. A CDPD term
MDN	Mobile Directory Number (DN)
ME	Mobile Equipment. Compare with MS
MEA	Message Encryption Algorithm
Media Access Control (MAC)	A method of controlling access to a transmission facility, for example, Ethernet, token ring, etc.
Mega	Prefix to indicate one million (e.g. Mega-bit). Abbreviated M
Megabit	One million bits of information.
MEGACO	Media Gateway Control - IETF Working Group
MEI	Mobility Event Indicator
MEMS	Micro-Electronic Mechanical System
meta-language	A language that can be used to define other languages. See ASN.1 and BNF
MeXe	Mobile Execution Environment
MF	(1)Multi-frequency tone signaling. Used for trunk signaling. (2)UIM Master File. Compare with EF and DF
MG	Media Gateway
MGC	MG Controller
MGCF	MG Control Function. Controls the Media Gateway
MGCP	MG Control Protocol. A VoIP call control standard. Also see older protocol SGCP
MGW	Media Gateway. Interface between packet environment of CN and circuit environment of PSTN
MHz	Million Hz. A measure of radio frequency
MIB	Management Information (Data)Bases
Microstrip Antenna	One consisting of a thin metallic conductor (patch) bonded to a thin grounded dielectric substrate and fed by a coaxial probe or a microstrip transmission line.
Microwave	A signal in the generic frequency range from above 1 GHz to an upper end of perhaps 30 or 40 GHz. This is the frequency range where coaxial cabled TEM mode signal propagation is viable.
MIN	Mobile Identification Number. 10 digit identifier of a mobile subscription. see IRM
MIN1	The last 7 digits of a MIN encoded in a weird, but compact, 24 bit binary format
MIN2	The first 3 digits of a MIN encoded in a very weird, but compact, 10 bit binary format
MIP	Mobile IP
MIPS	Million Instructions per Second. Measurement of processor speed
MLC	Mobile Location Center
MLPP	Multi-Level Precedence and Preemption
MM	Mobility Management
MMDS	Multi-channel Multi-Point Distribution Service
MMI	Man-Machine Interface
MMTA	MultiMedia Telecommunications Association. A subsidiary of TIA
MNC	E.212 Mobile Network Code (identifies an individual carrier, or a portion of a carrier network)
MNIC	Mobile Network Identification Code
MNID	Mobile Node Identification
MO	Mobile Originated/Originating
Mobile Cellular Systems	A high capacity system operating at 800-900 MHz using a frequency reuse scheme for vehicle and portable telephone communications.
Mobile Service	A radio communication service between mobile and fixed stations, or between mobile stations. Depending on whether one or more of the earth stations are on land, sea, or air, the service would be called land mobile, maritime mobile, or aeronautical mobile.
Mobile Station	A station in the mobile service intended to be used while in motion or during halts at unspecified points.
Mobile-Satellite Service (MSS)	A service that links mobile earth stations with base stations and with one another via one or more satellites.
Mobitex	An Ericsson Wireless Data protocol, once known as RAM Mobile Data in the US.
Monopole Antenna	One constructed above a ground plane producing a radiation pattern approximating that of a dipole in the half-space above the ground plane.
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.
MoU	(1)GSM Memorandum of Understanding. The guidelines under which GSM systems are implemented. (2)Minutes of Use. A common measure of the usage of a group of subscribers
MPC	Mobile Position Center. Interfaces between MSC, PDE, CRDB and ESME
MPCAP	Mobility Positioning Capabilities
MPCI	Mobile PCI
MPLS	Multi Protocol Label Switching. An IP protocol designed to provide preferred treatment to priority traffic to achieve a higher QoS
MRF	Media Resource Function. Provides conference bridges, announcements, tones and so forth to IP-based telephony networks
MS	Mobile Station (wireless phone)
MSA	Metropolitan Statistical Area. CGSA for urban cellular systems
MSB	Most Significant Bit or Byte. Compare with LSB
MSC	Mobile Switching Center
MSC-G	See Gateway MSC
MSC-H	See Home MSC
MSCIN	MSC Identification Number
MSC-O	See Originating MSC
MSC-V	Visited MSC. The MSC which a mobile is currently registered in
MSEIA	MS Emergency Information Assistance
MSID	Mobile Station Identifier. Either a MIN or IMSI
MSISDN	MS ISDN number. Same as MDN
MSK	Minimum Shift Keying. FSK where peak-to-peak FM deviation is half the data rate
MSRN	Mobile Station Roaming Number. The GSM equivalent of the ANSI-41 TLDN
MSS	Mobile Satellite System/Service
MS-SME	SME(1) embedded in MS
MT	Mobile Terminated/Termination
MTA	Major Trading Area
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)
Multimedia	In the context of mobile communications, a service that may combine voice, data, graphics and video information.
Multi-path	Wireless reception of multiple signals over one or more paths; in a normal line-of-sight fixed wireless link, the direct path dominates the received signal. During fading conditions or when the direct line-of-sight path is obstructed, one or more signals from objects causing reflections may be received. Reflected signals may cause constructive or destructive interference and the wireless link must be designed to operate reliably in multi-path situations.
Multiple Access	A method for accommodating more users in the same frequency band.
Multiplexing	Generally, a method of combining more than one signal or channel onto a single circuit or signal.
MUX	Multiplexer
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

N	Top

N-1 Switch	The switch responsible for LNP queries
NAA	Network Access Application
NACK	Negative ACK
NAI	Network Access Identifier
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)
Narrowband	A classification of the information capacity or bandwidth of a communication channel. Narrowband is generally taken to mean a bandwidth of 64 kbps or below.
NAS	Non-Access Stratum
NCAS	Non-Call Associated Signaling. Compare with CAS
NCGW	Network Capability Gateway
NCS	National Communication System. Responsible for US Government communication
NDC	E.164 National Destination Code
NE	Network Entity
NEBS	Network Equipment Building Systems
Network Layer	Layer 3 of the OSI model, at which routing occurs using the network address .
NFS	Number Field Sieve. Used in cryptography
NI	(1)Network Identity. (2)Number Incomplete
Nibble	Four bits
NID	Network Identification. A number that uniquely identifies a portion of a wireless carrier¹s total system. Used by TIA/EIA-95 systems
NIST	US National Institute of Standards and Technology
NL	Neighbor List
NMR	Network Measurement Results
NMSI	National Mobile Subscription Identity
NMT	Nordic Mobile Telephone. An analog cellular system available either in the 450 MHz or 900 MHz bands
Node	A termination point for two or more communications links. The node can serve as the control location for forwarding or switching data among the elements of a network.
Noise	Introduction of unwanted energy into a communications path that can change the information signal.
Noise-like	Having properties that cause the appearance of true random noise.
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
NPDB	Number Portability Database. A list of ported numbers and associated LRN's used for LNP routing
NPDE	Network PDE
NPDU	Network Protocol Data Unit. A packet
NPI	Numbering Plan Identifier
NPM	Non-Public Mode Service
NPR	MFCC Notice of Proposed Rulemaking
NRM	Network Reference Model (e.g. TIA/EIA/TSB-100)
NRN	Network Routing Number
NRTL	Nationally Recognized Test Lab
NRZ	Non-RZ
NS/EP	US National Security and Emergency Preparedness
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
NSP	Network service provider.
NSS	Network and Switching Subsystem
NSTAC	US National Security Telecommunications Advisory Council
NT	Network Termination
NTS	Number Translation Service
Nulls	In an antenna, near zero-level signals of sharp angular width seen in a radiation patterns. The opposite of lobes.
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
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	Top

O	Optional (e.g. for a parameter)
O&M	Operations and Maintenance
O/E	Odd/Even
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
O-BCSM	Originating BCSM
OBF	Ordering and Billing Forum of ATIS
OC-1	SONET service at 52 Mbit/sec
OC-12	Optical carrier 12, approximately 622 Mbps; a signal in the SONET hierarchy designed for fiber optic transmission.
OC-192	SONET service at 9,953 Mbit/sec
OC-3	Optical carrier 3, approximately 155 Mbps; a signal in the SONET hierarchy designed for fiber optic transmission.
OC-48	SONET service at 2,488 Mbit/sec
OC-768	SONET service at 38,813 Mbit/sec
OCDM	Optical Code Division Multiplexing
OCH	Optical Channel
OCN	Operating Company Number. US identifier for a telecom carrier
Octet	A snooty standards term for byte
ODB	Operator Determined Barring
OET	US FCC Office of Engineering & Technology
OFA	Optical Fiber Gateway
OFDMA	Orthogonal FDMA
OFS	Operational fixed services, a designation used by the FCC to describe private microwave networks licensed under Part 94.
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
OMC	Operations and Maintenance Center
Omnidirectionality	That property of an antenna exhibiting a non-directional pattern in a given plane.
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
OPSP	Origination Participation Service Provider
OPTS	Over-the-Air Programming Teleservice. See TIA/EIA-136
OQPSK	Offset Quadrature Phase Shift Keying; QPSK with an initial phase offset (of usually 45 degrees); OQPSK has less envelope AM than QPSK.
Originating MSC

Glossary of Wireless Terms