\\ More than 3500 Telecom abbreviations maintained by Ioan (Nini) Indreias // 1 A B C D E F G H I J K L M N O P Q R S T U V W X Y Small version 1G The first generation of analogue mobile phone technologies (AMPS, TACS and NMT) 2.5G The enhancement of GSM which includes technologies such as GPRS 2BIQ Two Bits, One Quantenary 2DRMS 2-Dimensional Root Mean Square 2G The second generation of digital mobile phone technologies (GSM, CDMA IS-95 and D-AMPS IS-136) 3G The third generation of mobile phone technologies covered by the ITU IMT-2000 family 3GPP The 3rd Generation Partnership Project 3GPP Third Generation Partnership Project 8PSK Octantal Phase Shift Keying A-bis Interface between the BSC and BTS in a GSM network A-TDMA Advanced Time Division Multiple Access A51/2/3/8X Encryption algorithms for GSM networks AA Administrative Authority AA Allocation Area AA Auto Answer AAA Authentication, Authorisation, and Accounting (OAM) AAB Automatic Answer Back AAC Alternate Access Carrier AAD Auditory Assistance Device AAL ATM Adaptation Layer AAP Alternate Access Provider AAR Automatic Alternate Routing AAR Automatic Alternative Routing AARP AppleTalk Address Resolution Protocol AAV Alternate Access Vendors AB Access Burst ABEND Abnormal end ABM Accunet Bandwidth Manager ABM Asynchronous Balanced Mode (HDLC) ABME ABM Extended ABR Area Border Router ABR Available Bit Rate (ATM) ABRD Automatic Baud Rate Detection ABS Alternate Billing Service ABS Alternative Billing Services ABS Application Bridge Server ABS Average Busy Stream ABSBH Average Busy Season Busy Hour (telephony) AC Access Connections AC Access Control (Token Ring, FDDI) AC Alternating Current AC Authentication Center ACA Asyncronous Communication Adapter ACB Annoyance Call Bureau ACC ANSI C++ Compiler ACCH Associated Control Channel (GSM) ACD Automatic Call Distribution/Distributor ACELP Algebraic Code Excited Linear Prediction ACF Access Control Field (DQDB) ACF Access Coordination Function ACF Advanced Communication(s) Function ACFA Advanced CMOS Frame Aligner ACG Automatic Call Gapping ACG Automatic Code Gapping ACI Answer Controller Interface ACIA Asyncronous Communications Interface Adapter ACK ACKnowledgement ACK Acknowledgment (DDCMP, BISYNC) ACL Access Control List ACM Address Complete Message (SS7) ACN Access Carrier Name ACN Advanced Communication Network ACN Application Context Name ACNA Automated Customer/Carrier Name and Address ACO Automatic Cut Off ACP Access/Action Control Point ACPI Advanced Configuration and Power Interface ACR Allowed Cell Rate ACR Anonymous Call Rejection ACR Automatic Call Routing ACS Asynchronous Communications Server ACSE Association Control Service Element (Application Layer) ACT Applied Computer Telephony ACTA America's Carriers Telecommunications Association ACTE Approvals Committee for Terminal Equipment ACTLU Activate Logical Unit (SNA) ACTPU Activate Physical Unit (SNA) ACTS Advanced Communications Technologies and Services ACTS Advanced Communications Technology Satellite ACTS Automatic Coin Telephone System ACU Alarm Control Unit ACU Antenna Combining Unit ACU Array Configuration Utility ACU Auto Callback Unit ACU Automatic Calling Unit ACUTA Association of College & University Telecommunications Administrators AD Administrative Domain ADAD Automatic Dialing-Announcing Device ADC Analog to Digital Converter ADCCP Advanced Data Communications Control Protocol (ANSI) ADD Automatic Dialing Device ADF Adapter Description File ADL Additional Directory Listing ADM Add/Drop Multiplexer ADMA Advanced DMA controller ADMD Administration Management Domain ADN Advanced Digital Network ADNS Advanced Data Network Solutions ADP Automatic Data Processing ADPCM Adapted Differential Pulse Code Modulation ADPCM Adaptive Differential PCM ADPCM Adaptive Digital PCM ADS-AIT Ameritech Advanced Data Services ADS Abstract Data Structure ADS Associated Directory Services ADSI Analog Display Services Interface ADSL Asymmetrical Digital Subscriber Line ADSP AppleTalk Data Stream Protocol ADSS All Dielectric Self-Supporting ADSU ATM DSU ADTS Automated Digital Terminal Systems AE Application Entity (GSM) AEP AppleTalk Echo Protocol AERM Alignment Error Rate Monitor AERM Alignment Error Rate Monitor (SS7) AF Audio Frequency AFC Automatic Frequency Control AFE Analog Front End AFI Authority and Format Identifier (ISO) AFP AppleTalk Filing Protocol AFPS Automatic Facility Protection Switching AFR Automatic Flexible Routing AFS Andrew File System AFSK Audio Frequency Shift Keying AGC Automatic Gain Control AGCH Access Grant Channel (GSM) AGND Analog Ground AGW Access Gateway AH Authentication Header AHT Average Handle Time AHT Average Hold Time AI Access Interface AI Artificial Intellegence AIM Asynchronous Interface Module AIN Advanced Intelligent Network AIN Advanced Intelligent Network (SS7) AIO Asynchronous Input/Output AIOD Automatic Identification of Outward Dialing AIP ATM Interface Processor (Cisco) AIRS Alarm Identification Reporting System (Harris) AIS-L Alarm Indication Signal-Line AIS-P Alarm Indication Signal-Path AIS-V Alarm Indication Signal-Virtual AIS Alarm Indication Signal (GSM) AIS Automatic Intercept System AIU Analog Interface Unit AIX Advanced Interactive Executive (IBM's Version of UNIX Operating System) ALI Address Location Information ALI Automatic Location Information ALIS Automatic Location Identification System ALIT Automatic Line Insulation Test ALJ Administrative Law Judge ALPS Airline Product Set (Cisco) ALPS Automatic Loop Protection Switching ALTS Alternate Local Transport Services ALU Arithmetic Logic Unit AM Active Monitor AM Administrative Module (AT&T 5ESS) AM Amplitude Modulation AMA Automatic Message Accounting AMACC Automatic Message Accounting Control Center AMADNS AMA Data Networking System AMATPS AMA Teleprocessing System AMD Advanced Micro Devices, Inc. AMI Alternate Mark Inversion AMI Alternative Mark Inversion AMIS Audio Messaging Interchange Specification AMLCD Active Matrix Liquid Crystal Display AMOS Access Mechanized Order System AMP Active Monitor Present (Token Ring) AMP Administrative Module Processor AMP AIN Maintenance Parameter AMPS Advanced Mobile Phone Service/System AMR Adaptive Multi-Rate codec AMRL Adjusted Main Ring Length AN Access Number ANC Access Network Controller ANI Automatic Number Identification ANI Automatic Number Identification (ISDN) ANM Ameritech Network Management ANM Answer Message ANP Automatic Numbering Plan ANR Automatic Network Routing ANS Advanced Network Systems ANSI American National Standards Institute ANVM Active Nonvolatile Memory ANW Advanced Netware AOA Angle Of Arrival AOC Advice Of Charge AoCC Advice of Charge Charging AoCI Advice of Charge Indication AOL America OnLine AON All Optical Network AOS Alternative Operator Services AP Access Point AP Access Provider AP Action Point AP Activation Platform AP Adjunct Processor AP Application Processor/Process/Program APA All Points Addressable APA Auto Port Aggregation APAD Asynchronous Packet Assembler/Disassembler APaRT Automated Packet Recognition/Translation (Cisco) APC Adjacent Point Code APD Avalanche Photo Diode APDU Application Protocol Data Unit API Application Program/Programming Interface APL Analog Private Line APN Access Point Name APNIC Asia Pacific Network Information Center APP Applications Portability Profile APPC Advanced Program-to-Program Communication (IBM) APPC Advanced Program-to-Program Communications APPN+ Next-generation APPN APPN Advanced Peer-to-Peer Networking (IBM) APR Alarm Processing Remote APS Automatic Protection Switching APSB Automatic Protection Switching Byte APT Telephony Applications System APTOS Automated Pricing, Terminals Operations & Services APTT Automatic Progression Trunk Testing APZ Telephony Control System AQL Acceptable Quality Level AR Access Registrar ARA AppleTalk Remote Access ARC ATM Research Consortium ARCnet Attached Resource Computer Network ARCOFI Audio Ringing Codec Filter ARCOS ARCOFI Coefficient Support Program ARD Automatic Ring Down ARE All Routes Explorer (Source Routing) ARFCN Absolute Radio Frequency Channel Number (GSM - UMTS) ARIB Association of Radio Industries and Businesses ARIN American Registry for Internet Numbers ARJ Admissions Reject (RAS) ARL Adjusted Ring Length ARM Asynchronous Response Mode (HDLC) ARP Address Resolution Protocol ARP Address Resolution Protocol (IETF) ARPA Advanced Research Project Agency ARPA Advanced Research Projects Agency ARPANET Advanced Research Projects Agency Network ARPU Average Revenue Per User ARQ Admissions Request (RAS) ARQ Automatic Repeat reQuest ARS Automatic Route Selection ARSB Automated Repair Service Bureau ARU Alarm Relay Unit ARU Automatic Response Unit ARU Audio Response Unit AS56 Accunet Switched 56 AS Autonomous System ASA Authorized Sales Agent ASA Average Speed of Answer ASAI Adjunct Switch Application Interface ASAM ATM Subscriber Access Multiplexer ASB Application Specific Bits ASBR Autonomous System Boundary Router ASC AIN Switch Capabilities ASCII American Standard Code for Information Interexchange ASCII American Standard Code for Information Interexchange (ANSI) ASCU Agent-Set Control Unit ASD Automated Software Distribution ASDS ACCUNET Spectrum of Digital Services (AT&T) ASE Amplified Spontaneous Emissions ASE Application Service Element (GSM) ASF Abstract Specification File ASI Alternate Space Inversion ASI ATM Service Interface ASIC Application Specific Integrated Circuit ASIP AlphaServer Intelligent Peripheral ASK Amplitude Shift Keying ASN.1 Abstract Syntax Notation One (ITU-T) ASN Abstract Syntax Notation (ITU-T) ASN Abstract System Notation ASN Auxiliary Signal Network ASP Active Server Pages ASP Advanced Speech Processor ASP AppleTalk Session Protocol ASP Application Service Provider ASP Assignment Source Point ASP Auxiliary Signal Path ASPI Advanced SCSI Programming Interface ASR Access Service Request ASR Answer-Seizure Ratio ASR Automatic Server Recovery (HP) ASR Automatic Speech Recognition AST Automatic Spanning Tree ASYNCH ASYNCHronous AT&T American Telephone and Telegraph Company AT Access Tandem switch AT Advanced Technology ATA Analogue Telephone Adapter ATAB Area Trunk Assignment Bureau ATB All Trunks Busy ATCP AppleTalk Control Protocol ATDM Asynchronous Time Division Multiplexing ATG Address Translation Gateway (Cisco) ATH Attention Hangup ATI Any Time Interrogation (GSM - UMTS) ATIS Alliance for Telecommunications Industry Solution ATM-LI ATM Link Identifier ATM-PCI ATM Protocol Control Information ATM-SDU ATM Service Data Unit ATM Asynchronous Transfer Mode ATM Automatic Teller Machine ATMM ATM Layer Management ATN Access Tandem Network ATP Acceptance Test Procedure ATP ALPS Tunneling Protocol. ATP AppleTalk Transaction Protocol ATP Application Transaction Programs ATS Advanced Telecommunications Services ATSC American Television Systems Committee ATSC Australian Telecommunication Standardization Committee ATU-C ADSL Transceiver Unit-Central office end ATU-R ADSL Transceiver Unit-Remote terminal end AU Access Unit AUC Authentication Center AUI Attachment Unit Interface AUI Attachment User Interface AUP Acceptable Use Policy AURP AppleTalk Update-based Routing Protocol AUSM ATM User Service Module AUX Apple UNIX AVBO Advanced Voice Busyout AVD Alternate Voice Data AVM ATM Voice Multiplexer AVR Automatic Voltage Regulator AVRU Automated Voice Response Unit AW Admin Workstation AW Administrative Weight AWG American Wire Gauge B-CDMA Broadband Code Division Multiple Access B-CPE Broadband Customer Premises Equipment B-ICI Broadband ISDN Inter-Carrier Interface B-ICI Broadband ISDN InterCarrier Interface B-ISDN Broadband Integrated Services Digital Network B-ISDN Broadband ISDN B3ZS Binary 3 Zero Substitution B6ZS Binary 6 Zero Substitution B8ZS Binary 8 bit Zero Substitution B8ZS Binary 8 Zero Substitution B Bearer channel B Bridge BA Balanced Asynchronous (HDLC) BACP Bandwidth allocation control protocol BAF Bellcore AMA Format BAIC Barring of All Incoming calls BAID Billing Account ID BAIF Billing Account Identification Facility BAN Billing Account Number BANCS Bell Administrative Network Communications System BAOC Barring of All Outgoing calls BAS Basic Activity Subset BAsize Buffer Allocation Size (DQDB, SMDS) BBN Bolt Baranek and Newman BBS Bulletin Board System BBWC Battery-Backed Write Cache Bc Committed Burst Size BCC Base station Color Code (GSM) BCC Base Station Colour Code (GSM - UMTS) BCC Block Calls Cleared (telephony) BCC Block Check Character (BISYNC) BCC Bus Control Card BCCH Broadcast Common Control Channel (GSM) BCCH Broadcast Control Channel (GSM) BCD Binary Coded Decimal BCD Blocked Calls Delayed BCD Blocked Calls Delayed (telephony) BCDIC Binary Coded Decimal Interchange Code BCH Blocked Calls Held BCH Broadcast Channels BCI Backward Call Indicators BCI Bell Canada International BCLB Broadband Connectionless Bearer Service (ATM) BCLID Bulk Calling Line Identification BCM Basic Call Model BCM Bit Compression Multiplexer BCOB Broadband Connection-Oriented Bearer Service (ATM) BCP Best Current Practices (RFC) BCR Blocked Calls Released BCS Basic Combined Subset BCS Business Communication Services BCSM Basic Call State Machine BD Bill Date BDCBB Battery Distribution Circuit Breaker Board BDCS Broadband Digital Cross-Connect System BDFB Battery Distribution Fuse Board BDSA Basic Digital Special Access BDT Telecommunications Development Bureau BE Back-end BE Block Error BECN Backward Explicit Congestion Notification BECN Backward Explicit Congestion Notification (LAPF) BEMS Business Exchange Measured Service BER Basic Encoding Rule(s) BER Bit Error Rate/Ratio BERT Bit Error Rate Test BES Basic Exchange Service BEtag Beginning-End Tag (DQDB, SMDS) BFCV Binary Facility Coding Value BFI Bad Frame Indicator (GSM) BG Billing Group BG Business Group BGID Business Group Identification BGP4 BGP Version 4 BGP Border Gateway Protocol (IETF) BGS Business and Government Services (USW Enterprise) BGW Billing Gateway BHCA Busy Hour Call Attempt(s) BHCC Busy Hour Call Completions BIA Burned-in MAC address BIB Backward Indicator Bit BIB Backward Indicator Bit (SS7) BIBR Backward Indicator Bit Received BIBT Backward Indicator Bit to be Transmitted BIBX Backward Indicator Bit eXpected BICC Bearer Independent Call Control BICI Broadband Inter-Carrier Interface BICRoam Barring of Incoming Calls while Roaming BIGA Bus Interface Gate Array (Cisco) BIND Berkeley Internet Name Domain (DNS) BinHex Binary Hexadecimal BIOS Basic Input/Output System BIP Bit Interleaved Parity (SONET, SDH) BIPI Billing Plug-In BISDN Broadband Integrated Services Digital Network (ISDN) BISUP Broadband ISUP (ISDN User Part) BISYNC BInary SYNChronous (also BSC) BISYNC Binary Synchronous Communications protocol (IBM) BIT BInary Digit BITNET Because It's Time Network BITS Building Integrated Timing Supply BIU Basic Information Unit BL Basic Link BLER BLock Error Rate BLI Busy Lamp Indicator BLSR Bidirectional Line Switched Ring (SONET) BLU Basic Link Unit (SNA) BM Broadband Modem BN Billing Number BNC Bayonet Neil Councilman BNF Backus Naur Form BNI Broadband Network Interface BNM Broadband Network Module BNN Boundary Network Node BNR Bell Northern Research (subsidary of BCE) BNS Bill Number Screening BNS Broadband Network Service BOB Breakout Box BOBI Break-out/Break-in (Cisco) BOC Bell Operating Company BOCP Business Optional Calling Plan BOIC Barring of Outgoing Internaltional Calls BOICexHC Barring of Outgoing International Calls except those to the Home Country BOM Beginning of Message (DQDB, SMDS) BOOTP Bootstrap Protocol BORSCHT Battery feed, Overvoltage protection, Ringing, Signaling, Coding, Hybrid and Testing BP Binding Post BPAD BISYNC Packet Assembler/Disassembler (PSPDN) BPDU Bridge Protocol Data Unit (LAN) BPI Baseline Privacy Interface BPOP Building Point of Presence BPR Business Process Re-engineering BPRZ Bipolar Return to Zero BPS Bits Per Second BPV Bipolar Violation BPX Broadband Packet Exchange (StrataCom) BRA Basic Rate Access BRADS Bellcore Rating Administrative Data System BRCS Business and Residence Centrex Services BRE Bridge Relay Element BRF Bridge Relay Function BRI Basic Rate Interface BRI Basic Rate Interface (ISDN) BRIDS Bellcore Rating Input Database System BRITE Basic Rate Interface Transmission Equipment/Extension BRLU Broadband Remote Line Unit BRS Business Recovery Service BRSU Broadband Remote Switching Unit BS Base Station BS Bearer Service BSA Basic Service Arrangement BSBH Busy Season Busy Hour (telephony) BSC Base Station Controller (GSM) BSC Binary Synchronous Communications protocol (IBM) BSC Bisynchronous Communications BSD Berkeley Software Distribution BSE Basic Service Element BSIC Base Station Identity Code (GSM) BSN Backward Sequence Number (SS7) BSNR Backward Sequence Number Received BSNT Backward Sequence Number to be Transmitted BSP Bell System Practice BSRF Basic System Reference Frequency BSS Base Station Subsystem (GSM) BSS Basic Service Set BSS Basic Synchronized Subset BSS Broadband Switching System BSS Broadcasting Satellite Service BSSGP BSS GPRS Protocol BSSMAP Base Station Subsystem Mobile Application Part (GSM) BSTUN Block Serial Tunnel BT Burst Tolerance (ATM) BTA Basic Trading Area BTA Basic Trading Areas (Rand McNally) BTAM Basic Telecommunications Access Method (SNA) BTN Billing Telephone Number BTS Base Transceiver Station (GSM - UMTS) BTU Basic Transmission Unit Bureau of Standards) BUS Broadcast and Unknown Server BVA Billing Validation Application BVCI BSSGP Virtual Vonnection Identifier BVI Bridge Group Virtual Interface BX.25 AT&T implementation of X.25 BXM Broadband Switch Module C-ISUP Proprietary Cisco protocol based on ISUP C/(N+I) Carrier to Noise plus Interference Ratio C/I Carrier to Interference Ratio C/N Carrier to Noise ratio C/R Command/Response C/R Control/Response Indication Bit C Curb CA Call Appearance (Telecom) CA Certificate/Certification/Certifying Authority CA Collision Avoidance CA Communications Assistant CA Conditional Access (SAT) CABS Carrier Access Billing System CAC Carrier Access Code CAC Connection Admission Control CACD Commission Advisory and Compliance Division CAD Computer Automated/Aided Design CAD Computer Automated/Aided Dispatch CAD Computer Automated/Aided Drafting CADS Computer Automated/Aided Dispatch System CAE Computer Automated/Aided Engineering CAGR Compound Annual Growth Rate CAI Common Air Interface CAL Customer Access Line CAM Cisco Access Manager CAM Computer Automated/Aided Manufacturing CAM Content-Addressable Memory CAMA Centralized Automatic Message Accounting CAMEL Customised Applications for Mobile network Enhanced Logic (3GPP 23.078) CAN Cosmopolitan Area Network CAP CAMEL Application Part CAP Carrierless Amplitude/Phase modulation CAP Competitive Access Provider CAR Cisco Access Registrar CAR Committed access rate CAR Current Activity Report CAS Centralized Attendant Service CAS Channel Associated Signaling CASE Common Application Service Element CASE Computer Aided Software Engineering CAT Carrier Access Tariff CAT Computer Aided Tomography CATIA Computer Assisted Three-dimensional Interactive Application CATV CAble TeleVision CATV Community Antenna TeleVision CAU Cable Access Unit CB Cell Brodcast (GSM) CB Channel Bank CB Citizens Band CBAC Context-Based Access Control CBC Cell Broadcast Center (GSM) CBC Cipher Block Chaining CBCH Cell Brodcast Channel (GSM) CBCU Centralized Broadband Control Unit CBDS Connectionless Broadband Data Service(s) CBEMA Computer and Business Equipment Manufacturers Association CBQ Class-Based Queuing CBR Constant Bit Rate CBR Constant Bit Rate (ATM) CBS Cell Broadcast Services (GSM) CBWFQ Class-Based Weighted Fair Queueing CBX Computerized Branch eXchange CC Call Context CC Call Control CC Cluster Controller (IBM) CC Connect Confirmation CC Country Code (ITU-T) CC Customer Care CCA Call Control Adjunct CCAPI Call Control API CCB Call Control Block CCB Customer Care and Billing CCBS Call Completion on Busy Subscriber CCC Clear Channel Capability CCC Customer Care Center CCCH Common Control Channel (GSM) CCD Charge Coupled Device CCE Consistency Check End CCF Call Control Function CCF Common Citizen Focus CCG Central Clock Generator CCI Common Client Interface CCIE Cisco Certified Internetwork Expert CCIR international radio consultative committee CCIR International Radio Consultative Committee (ITU) CCIS Common Channel Inter-office Signaling (AT&T) CCITT Consultive Committee on International Telephony and Telegraphy (ITU) CCL Common Carrier Line CCLC Carrier Common Line Charge CCNA Cisco Certified Network Associate CCNC Common Channel Signaling Network Control CCO Cisco Connection Online CCOT Cross Office Transfer Time CCR Commitment, Concurrency and Recovery (Application Layer) CCR Consistency Check request CCR Customer Control Reconfiguration CCR Customer Controlled Reconfiguration CCRU Customer Care Retention Unit CCS7 Common Channel SS7 CCS Centi Call Seconds (Hundred seconds calls per hour) CCS Common Channel Signaling CCS Customer Calling Services CCSA Common Control Switching Arrangement CCSN Customer Contact Services Node CCSRC Cisco Subscriber Registration Center CCSS7 Common Channel SS7 (AT&T) CCTV Closed-Circuit TeleVision CCU Common Control Unit CCXML Call Control XML CD-ROM Compact Disc-Read Only Memory CD Call Disconnect (SS7) CD Carrier Detect CD Circuit Details CD Collision Detection (LAN) CD Compact Disc CDAR Customer Dialed Account Recording CDB Call Detail Block CDC Control Data Corporation CDDI Copper Distributed Data Interface CDE Call Detail Element CDF Channel Definition Format CDMA-1X-EV-DO A variant of CDMA 1X which delivers data only CDMA-1X The first generation of CDMA 2000 CDMA Code Division Multiple Access CDO Community Dial Office CDP Cisco Discovery Protocol CDP Customized Dialing Plan CDPD Cellular Digital Packet Data CDPSK Coherent Differential Phase Shift Keying CDR Call Detail Record (OAM) CDR Call Detail Recorder CDR Call Drop Rate CDSL Customer Digital Subscriber Line CDT Central Daylight Time CDU Customer Data Unit CDV Cell Delay Variation (ATM) CDVT Cell Delay Variation Tolerance (ATM) CED Caller Entered Digits CEF Cisco Express Forwarding CEI Comparably Efficient Interconnection CEI Connection Endpoint Identifier (LAPD) CELL1 Cellular One CELP Code Excited Linear Prediction CELP Code Excited Linear Prediction (compression) CENTREX CENTral Exchange CEO Chief Executive Officer CEP Certificate Enrollment Protocol CEP Circular Error Probable CEPT Conference European on Post and Telecommunications CEPT Conference of European Postal and Telecommunications Administrations CER Cell Error Ratio (ATM) CERN European Council for Nuclear Research CERT Computer Emergency Response Team CES Circuit Emulation Service CES Connection Endpoint Suffix CESAR Customer's Enhanced System for Access Requests CET Cisco Encryption Technology CEV Controlled Environment(al) Vault CF Call Forwarding CF Coin First CFA Carrier Failure Alarm CFB Call Forwarding on Busy (SS) CFBNA Call Forwarding for Busy and NoAnswer CFN Call Forward Number CFNRy Call Forwarding on No Reply (SS) CFO Chief Financial Officer CFU/B/NR Call Forwarding Unconditional/Busy/No Reply CFU Call Forwarding Unconditional (SS) CGA Carrier Group Alarm CGB Circuit Group Blocking Message CGF Charging Gateway Function CGI Cell Global Identification (GSM) CGI Cell Global Identity (MCC + MNC + LAC + CID) CGI Common Gateway Interface CGI Common Gateway Interface (Protocol) CGM Computer Graphics Metafile CGSA Cellular Geographic Service/Serving Area CGU Circuit Group Unblocking Message CGW Customer Gateway CH Cell Header CHAP Challenge Handshake Authentication Protocol CHE Cable HeadEnd CHFP Certified Human Factors Professional CHI Conference on Human factors In computing systems CHO Choke Packet CHTML Compact Hyper Text Markup Language CI Carrier Interconnection CI Carrier to Interference ratio CI Cell Identity (GSM) CI Credit Information CI Customer Installation CIA Classical IP over ATM CIB CRC32 Indication Bit (DQDB, SMDS) CIBER Cellular Intercarrier Billing Exchange Roamer Record CIC Carrier/Circuit Identification Code CIC Country Indicator Code CICS Customer Information Control System CID Caller Identification CID Cell ID (GSM - UMTS) CID Channel ID CID Craft Interface Device CIDR Classless Interdomain Routing (IETF) CIDS Calling Identity Delivery & Suppression CIDX Chemical Industry Data Exchange CIF Client Interface Module (SZ) CIF Common Intermediate Format CIIII Computer Inquiry III (DOJ) CIM Computer Integrated Manufacturing CIO Chief Information Officer CIP Channel Interface Processor (Cisco) CIR Committed Information Rate CIR Committed Information Rate (FR) CIRC Cross Interleaved Reed-Solomon Code CISC Complex Instruction Set Computer CIT Collect Information Toll CIT Collect Information Tool CIT Computer Integrated Telephony CIU Communications Interface Unit CIX Commercial Internet eXchange CKL Circuit Location CKSN Ciphering Key Sequence Number (GSM) CKTINT Circuit Interworking software CL&F Common Look and Feel CL Connectionless CL Copper Loop CLASS Custom Local Area Signaling Services CLASS Custom Local Area Signaling Services (Bellcore) classification) CLAW Common Link Access for Workstations CLC Carrier Liaison Committee CLC Common Language Code CLC Competitive Local Carrier CLCI Common Language Code Identifier CLEC Competitive Local Exchange Carrier CLEI Common Language Equipment Identifier CLF Common Language Facility CLFI Common Language Facility Identification CLI Caller ID CLI Command Language Interpreter CLI Command Line Interface (OAM) CLID Calling Line IDentification (ISDN, CLASS) CLIP Calling Line Identification Presentation (SS) CLIR Calling Line Identification Restriction (SS) CLLI Common Language Location Identifier/Identification CLLM Consolidated Link Layer Management (FR) CLNP Connectionless Network Protocol (ISO, ITU-T) CLNS Connectionless Network Service (ISO, ITU-T) CLP Cell Loss Priority CLP Cell Loss Priority (ATM, CLP Bit) CLR Clear CLS Cisco Link Services CLS Connectionless Service CLSI Cisco Link Services Interface CLTP Connectionless Transport Protocol CLTS Connectionless-mode Transport Service CM Cable Modem CM Communications Module (AT&T 5ESS) CM Conference Manager CM Connection Management CM Connection Manager CMC Cellular Mobile Carrier CMDB Centralized Message DataBase CMDR Call Management Detail Records CMDS Centralized Message Distribution System CMI Coded Mark Inversion CMI Control Mode Idle CMIP Common Management Information Protocol (ISO, ITU-T) CMIS Common Management Information Service/System CMISE Common Management Information Service Element (ISO, ITU-T) CMNM Cisco MGC Node Manager CMNS Connection-Mode Network Service CMOL CMIP Over LLC CMOS Complementary Metal-Oxide Semiconductor CMOT CMIP Over TCP/IP CMP Communications Module Processor CMRS Commercial Mobile Radio Services CMS Call Management System {AT&T) CMT Connection Management (FDDI) CMTS Cable Modem Termination System CMU Carnegie Mellon University CN Common Name CNA Customer Number Address CNAB Call Name Delivery Blocking CNCA Carrier Non-Compatible Applications CNE Certified NetWare Engineer CNG CalliNG CNM Customer Network Management CNMA Customer Network Management Agent CNS/AD Cisco Networking Services for Active Directory CNS Complementary Network Service(s) CO-ACD Central Office Automatic Call Distributor CO-LAN Central Office-Local Area Network CO Central Office CO Connection-Oriented COAX COAXial COC Central Office Connection COCOT Customer Operated COin Telephone Code CODEC Coder plus DECoder CODEC COder-DECoder COFA Change of Frame Alignment COI Community Of Interest COLA Cost Of Living Adjustment COLA Customer On Line Authentication COLAN Central Office-based LAN COLP Connected Line Identification Presentation (SS) COLR Connected Line Identification Restriction (SS) COM Continuation of Message (DQDB, SMDS) COMC Communications Controller (SNA) COMPANDER COMpressor/exPANDER CONF CONFerence CONP Connection-Oriented Network Protocol CONS Connection-Oriented Network Service (ISO, ITU-T) COP Customer Ordering Platform COPI Collector Plug-In COPS Common Open Policy Service COPT Customer Owned Public Telephone CORBA Common Object Request Broker Architecture COS Class Of Service COS Corporation for Open Systems COSE Common Open Software Environment COSMOS Central Office System for Mainframe Operations COT Central Office Terminal COT Continuity Test Message COTS Commercial Off-the-Shelf (stuff) CP Cell Payload CP Connection Point CP Control Point CP Control/Coordination Processor CP Customer Premises CPC Call Processing Control CPC Calling Party Category CPCN Certificate of Public Convenience and Necessity CPCS Call Processing Control System CPCS Common Part Convergence Sublayer CPE Certified Professional CPE Customer Premise(s) Equipment CPG Call Progress Message CPI/C Common Programming Interface for Communication CPI Computer-PBX Interface CPI Consumer Price Index CPM Cost Proxy Model CPNI Customer Proprietary Number/Network Information CPNIE Called Party Number Information Element CPP Calling Party Pays CPP Combinet Proprietary Protocol (Cisco) CPR Core Process Re-engineering CPS Customer Premises System CPS Cycles Per Second CPU Central Processor/Processing Unit CPUC California Public Utilities Commission CQ Custom Queuing CQM Circuit Group Querry (SS7) CQR CQM Response (SS7) CR Call Reference CR Certificate Request CR Conditional Requirement CR Connect Request (SS7) CRA Circuit Reservation Acknowledgment Message CRC Cyclic Redundancy Check(word) CRC Cyclical Redundancy Checking CRED Credit Card Calling CREF Connection Refused CRF Concentrator Relay Function (ATM) CRIS Customer Records Information System CRL Certificate Revocation List CRM Circuit Reservation Message CRM Customer Relationship Management crossconnect frame CRP Customer Routing Point CRS Cell relay Service CRS Configuration Report Server CRT Cathode Ray Tube CRTC Canadian Radio-television and Telecommunications CRU Customer Retention Unit CRV Call Reference Value (Q.931) CS-1 Capability Set 1 CS-ACELP Conjugate Structure Algebraic Code Excited Linear Prediction (compression) CS-PDU Convergence Sub-layer PDU CS1 Capabilities Set 1 CS2 Capabilities Set 2 CS Call Segment CS Capability Set CS Carrier Services CS Configuration Server Module(SZ) CS Convergence Sublayer (ATM) CSA Call path Services Architecture CSA Canadian Standards Association CSA Carrier Serving/Service Area(s) CSA Custom Service Arrangement CSAP Core Service Access Point CSB Customer Service Bureau CSC Circuit Supervision Control CSC Common Signaling Channel CSC Customer Service Center CSDC Circuit Switched Digital Capability CSDN Circuit Switched Data Network CSDS Circuit Switched Digital Service CSDU Core Service Data Unit CSE CAMEL Service Environment CSFS Customer Support Forwarding Service CSH Convergence Sublayer Header CSI Called Subscriber Identification CSIMA Client Side Image Map Authoring CSLIP Compressed Serial Link Internet Protocol CSM Call Switching Module CSM Cisco Service Management system of Operations, Administration, Maintenance, and Provisioning (OAM&P) CSMA/CA CSMA with Collision Avoidance (LAN) CSMA/CD Carrier Sense Multiple Access with Collision Detection CSMA/CD CSMA with Collision Detection (LAN) CSMA Carrier Sense Multiple Access CSMA Carrier Sense Multiple Access (LAN) CSN Central/Customer Service Node CSNET Computer Science Network CSNP Complete Sequence Number PDU CSO Composite Second Order CSP Chip Scale Package CSPDN Circuit Switched Public Data Network CSR Consistency Check Request CSR Customer Service Record CSR Customer Service Representative (OAM) CSS Customer Support System CST Central Standard Time CST Convergence Sublayer Trailer CST Cooperative Scheduled Testing CSTA Computer Supported Telecommunications Application CSU Channel Service Unit CSV Comma Separated Values CT0 Zero generation cordless telephony (analogue technology and severe limitations in terms of range and security) CT1 First generation cordless telephony (greater range and security) CT2-CAI Second generation cordless telephony-common air interface CT2 Second generation cordless telephony (digital with greater range, improved security and a wide range of new functionalities) CT Call Transfer CT Call Type CT Channel Termination CT Common Transport CT Computer Telephony CT Computerized Tomography CT Cordless Telephone/Telephony CTA Cordless Terminal Adaptor (DECT) CTB Composite Triple Beat CTD Cell Transfer Delay (ATM) CTI Computer Telephony Integration CTIA Cellular Telecommunications Industry Association CTM Cordless Terminal Mobility CTR Common Technical Regulation, part of the ETSI standardization process CTS Clear To Send CTS Clear To Send (EIA-232-E) CTS Common Transport Semantic (IBM) CTU Channel Test Unit CTX CenTreX system number CU Channel Unit CU Coding Unit CU Control Unit CUG Closed User Group (GSM) Custom Service Arrangement CV Coding Violation CVM Cluster Veritas Volume Manager CVN Customer Virtual Network CVR Circuit Validation Response Message CVSD Continuously Variable Slope Delta Modulation CVSDM Continual Variable Slope Delta Modulation CVT Circuit Validation Test Message CW Call Waiting (SS) CWAF Cisco Web Application Framework CWC Center Weight Control CWID Call Waiting IDentification service CWIDO Call Waiting IDentification with Options service CxBus Cisco Extended Bus D-AMPS Digital AMPS (US wireless standard, IS-136) D-H Diffie-Hellman (algorithm) D-WDM Dense-Wavelength Division Multiplexing D/I Drop and Insert D3 Third generation channel bank (24 chans on T1) D4 Fourth generation channel bank (48 voice chans on 2 T1's or 1 T-1C) D Data Channel DA Destination Address (LAN) DA Device Address (SNA) DA Digital Access DA Directory Assistance DA Distribution Area DAC Digital to Analogue Convertor DAC Dual Attachment Concentrator (FDDI) DACK DMA ACK DACS Digital Access and Cross-connect System (AT&T) DACS Digital Access and Crossconnect System DAEDR Delimitation, Alignment and Error Detection procedure in Receive Direction DAL Dedicated/Direct Access Line DAMA Demand Assigned Multiple Access DAML Digital Added Main Line DAN DECT Access Node DAO Directory Assistance Only DAP Data Access Protocol (DEC's DNA - Application Layer) DAP Directory Access Protocol DAP Directory Access Protocol (AppleTalk) DAP Document Application Profile DARPA Defense Advanced Research Project Agency DARPA Defense Advanced Research Projects Agency DAS Dual Attachment Station DAS Dual Attachment Station (FDDI) DAS Dynamically Assigned Socket DASD Direct Access Storage Device DAT Digital Audio Tape DAU Data Adapter Unit DAVIC Digital Audio Video Council DB2 DATABASE2 (IBM) DB Database dB decibel DB Dummy Burst DBAC DataBase Administration Center DBAS DataBase Administration System DBCS Data Bank Control System DBCS Double-Byte Character Sets DBIF Database Interface Module (SZ) DBMS Database Management System DBN Dial-Back Number DBOS Data Bank Organization System DBS Direct Broadcast Satellite DBS Direct Broadcats Satellite DBSS Data Bank Security System DBW Decibel per Watt DC Direct Current DCA Digital Communications Associates DCA Document Content Architecture DCA Dynamic Channel Assignment DCB Digital Channel Bank DCC Data Communications Channel (SONET) DCC Data Country Code DCC Digital Control Channel DCCH Dedicated Control Channel (GSM, SDCCH, SACCH and FACCH) DCCX Direct Circuit Control Exchange DCE Data Circuit-terminating Equipment DCE Data Communications Equipment DCE Distributed Computing Environment DCER Data Circuit-terminating Equipment Ready DCF Dispersion Compensating Fiber DCF Distributed Coordination Function DCH Data Clearing House DCM Digital Circuit Multiplication (same as DSI) DCN Data Communications Network DCO Digital Central Office DCOM Distributed Component Object Model DCP Designated Carrier Plan DCP Digital Communications Protocol DCPSK Differentially Coherent Phase Shift Keying DCR Dynamically Controlled Routing DCS-1800 Digital Cordless Standard DCS Digital Communications System DCS Digital Crossconnect System DCT Discrete Cosine Transform DD Database Description DD Domain Directory DDCMP Digital Data Communications Message Protocol (DNA) DDD Direct Distance Dialing DDI Direct dial-in DDL Data Definition Language (SQL) DDLMP Digital Equipment Corporation data link control DDM Digital Data Multiplexer DDM Distributed Data Management DDN Defense Data Network DDP Datagram Delivery Protocol (AppleTalk) DDR Dial-on-Demand Routing DDR Double Data Rate DDR Double Data Rate (SDRAM) DDS Dataphone Digital Service DDS Dataphone Digital Service (AT&T) DDS Digital Data Service DDSD Delay Dial Start Dial DDSN Distributed Diagnostics and Service Network DE Discard Eligibility DE Discard Eligibility (LAPF) DEA Data Encryption Algorithm DEA Digital Exchange Access DEC Digital Equipment Corporation DECmcc DEC Management Control Center DECT Digital European Cordless Telephone DECT Digitally Enhanced Cordless Telecommunications DEK Data Encryption Key DEPSK Differential Encoded Phase Shift Keying DER Distinguished Encoding Rules DES Data Encryption Standard DES Data Encryption Standard (NIST) DES Destination End Station DES Digital Encryption Standard DF Distributing Frame DF Don't Fragment (IP) DFC Data Flow Control DFL Distributed Feedback Laser DFRI Datacom Reference Frame Input DFS Distributed File System DFSK Double Frequency Shift Keying DHCP Dynamic Host Configuration Protocol DIA Document Interchange Architecture DID Direct Inward Dialing DID Direct(ed) Inward Dialing DIDR Direct Inward Dial Number Range DILIC Dual In-Line Integrated Circuit DIMM Dual In-line Memory Module DIMM Dual Inline Memory Module DIP Dual In-line Package DISA Direct inward station access DISA Direct Inward System Access DISC Disconnect DIT Directory Information Tree DL Data Link DLC Digital Loop Carrier DLCI Data Link Connection Identifier/Indicator (GSM, LAPD, LAPF) DLCI Data Link Connection Indicator DLE Data Link Escape (BISYNC) DLH Data Link Layer Header DLL Dial Long Line DLL Dynamic Link Library DLM Distributed Lock Manager DLR Design Layout Record DLR Destination Local Reference DLS Data Link Switching DLSw+ Data-Link Switching plus (Cisco) DLT Data Link Layer Trailer DLU Dependent LU DLU Digital LU DLUR Dependent LU Requester DLUS Dependent LU Server DM Delta Modulation DM Dialogue Management DM Disconnected Mode (HDLC) DMA Direct Memory Access DMAC destination MAC DMAC Direct Memory Access Control DMB Dynamic Multipoint Bridging DME Distributed Management Environment DMI Desktop Management Interface DMI Digital Multiplex(ed) Interface DML Data Manipulation Language (SQL) DMP Data Movement Processor (Cisco) DMP Device Management Protocol DMPB Digital Multipoint Bridging DMS Digital Modular Switch DMS Digital Multiplex Switch DMS Digital Multiplex System DMT Discrete Multitone Technology DMTS Distinguished Member of Technical Staff DN Dialed Number DN Directory Number DN Directory Number (SS7) DN Distinguished Name (X.500) DNA Data Network Address DNA Digital Network Architecture DNA DoNotAge (bit) DNCF Directory Number Call Forwarding DNHR Dynamic Nonhierarchical Routing DNI Data Network Interface DNIA Dialed Number Identification Service DNIC Data Network Identification Code DNIC Data Network Identification Code (X.121) DNIC Data Network Interface (2B+D ISDN) DNIS Dialed Number Identification Service DNS Domain Name System DNS Domain Name System (IETF) DNSP Distributed Networked Services Platform DNU Digital Networking Unit DOC Dynamic Overload Control DOCSIS Data Over Cable Service Interface Specification DOD Department Of Defence DOD Direct Outward Dialing DOI Domain Of Interpretation DOMSTATS Domestic Satellite Carriers DOS Disk Operating System DOS Domestic Operator Service DOV Data Over Voice DOW Day Of Week DP Data Processing DP Detection Point DP Dial Pulse DPA Distributed Power Architecture DPBX Digital Private Brance Exchange DPBX Digital Private Branch eXchange DPC Destination Point Code (SS7) DPCM Differential Pulse Code Modulation DPDU Data (link) Protocol Data Unit DPE Digital Parity Error DPG Digital Pair Gain DPL Digital Power Line DPM call Defect Per Million DPNSS Digital Private Network Signaling System (BT) DPO Dial Pulse Originate DPSK Differential Phase Shift Keying DPSK Digital Phase Shift Keying DPT Dial Pulse Terminate DPT Dynamic Packet Transport DQDB Distributed Queue Dual Bus DQDB Distributed Queue Dual Bus (IEEE 802.6) DQPSK Digital Quadrature Phase Shift Keying DR Digit Receiver DRA Division of Ratepayer Advocates DRAD Digital Remote Antenna Driver DRAM Dynamic Random Access Memory DRAM Dynamic Random Access Memory (RAM) DRCS Dynamically Redefinable Charectes Sets DRDA Distributed Relational Database Architecture (IBM) DRP Director Response Protocol (Cisco) DRP Dispute Resolution Procedure DRX Discontinous Reception (GSM) DS-0 Digital Signal level 0 DS-1 Digital Signal level 1 DS-2 Digital Signal level 2 DS-3 Digital Signal level 3 DS-CDMA Direct Sequence CDMA DS0 Digital Signal Zero - 64 Kb/s data/voice chan DS1 Digital Signal One (DS0 x 24 = 24 DS0) DS2 Digital Signal 2 (DS1 x 4 = 96 DS0) DS3 Digital Signal 3(DS2 x 7 = 672 DS0) DS Data Services DS Digital Signal DS Directory Services DS Directory Synchronization DSA Digital Signature Algorithm DSA Directory System Agent DSAP Destination Service Access Point (LLC) DSC Digital Switch Corporation DSE Data Switching Equipment DSE Data Switching Exchange DSF Dispersion-Shifted Fiber DSG Data Systems Group DSI Digital Speech Interpolation DSL Digital Subscriber Line DSLAM Digital Subscriber Line Access Multiplexer DSMA/CD Digital Sense Multiple Access with Collision Detection DSMA Digital Sense Multiple Access DSN Data Source Name (ODBC) DSN Delivery Status Notification DSN Digital Switched Network DSODP Digital Service Office Dataport DSP Digital Signal Processor/Processing DSP Directory Service Protocol DSP Display System Protocol (packet switching) DSP Domain Specific Part DSPU Downstream Physical Unit DSR Data Set Ready DSRR Digital Short Range Radio DSS Decision Support System DSS Digital Subscriber Signaling system (ISDN, B-ISDN) DSS Digital Switched Services DSSS Direct Sequence Spread Spectrum DSU Data/Digital Service Unit DSX Digital Signal Cross-connect DSX termination hardware for DS1 and DS3's DT Dedicated Transport DTAU Digital Test Access Unit DTD Document Type Declaration DTE Data Terminal Equipment DTF Dial Tone First DTF Digital Transmission Facility DTH Direct to Home DTI Digital Trunk Interface DTL Designated Transit List DTLU Digital Terminal Line Unit DTMF Dual Tone Multi Frequency DTMF Dual Tone Multi(ple) Frequency DTP DDSN Transfer Protocol DTP Distributed Transation Processing DTR Data Terminal ready DTR Data Terminal Ready (EIA-232-E) DTS Data Terminal Set DTS Digital Terminal Systems DTS Digital Transmission Systems DTU Data Terminal Unit DTV Digital Television DTZ Discontinuous Transmission DUA Directory User Agent DUAL Diffusing Update Algorithm (Cisco) DUP Data User Part DVB Digital Video Broadcasting DVI Digital Video Interleaved DVM Data Voice Multiplexer DVM Digital Volt Meter DVMRP Distance Vector Multicast Routing Protocol DVT Digital Video Terminal DVVI Data, Voice, Video integration DWDM Dense Wavelength Division Multiplexing DX Duplex DXC Digital Cross Connect DXI Data eXchange Interface DXI Data Exchange Interface (ATM, SMDS) E&M Ear and Mouth EA Address field Extension (HDLC) EA Equal Access EA Extended Address EAD Expedited Application Docket EADAS Engineering and Administration Data Acquisition System EADASNM EADAS Network Administration EAEO Equal Access End Office EAI Enterprise Application Integration EAMF Equal Access Multifrequency EAOSS Exchange Access Operator Service Signaling EAP Extensible Authentication Protocol EARN European Academic Research Network EARS Easy Access Request System EAS Equal Access Signaling EAS Extended Area Service EBAT Electronic Bill Analysis Tool EBCDIC Extended Binary Coded Decimal Information/Interchange Code EBS Electronic Business Sets EBU European Broadcasting Union EC Echo Canceling EC Electrical Carrier EC European Community ECC Error Checking/Correction Code ECDSA Elliptic Curve Digital Signature Algorithm ECM Error Correction Mode ECMA European Computer Manufacturer Association ECN Electronic Communication Network ECN Explicit Congestion Notification (FR) ECSA Exchange Carriers Standards Association ECTF Enterprise Computer Telephony Forum ED Ending Delimiter (LAN) EDFA Erbium-Doped Fiber Amplifier EDGE Enhanced Data rate for GSM Evolution EDGE Enhanced Data rate(s) for GSM Evolution EDI Electronic Data Interchange (ANSI) EDI Electronic Data Interexchange EDIFACT EDI for Administration, Commerce, and Transportation EDIFACT Electronic Data Interchange For Administration, Commerce, and Trade (ANSI) EDO Extended Data Out EDP Electronic Data Processing EDP Event Detection Point EDSX Electronic Digital Signal Cross-Connect EECM End-to-End Call Manager EEO Equal Employment Opportunities EEO Extremely Elliptical Orbit EEPROM Electrically Erasable Programmable Read-Only Memory EF Entrace Facility EFCI Explicit Forward Congestion Indicator (ATM) EFD Event Forwarding Discriminator EFM Eight-Fourteen Modulation EFR Enhanced Full Rate EFS End-of-Frame Sequence (LAN) EFS Error Free Second(s) EFS Error Free Seconds EFT Electronic Funds Transfer EGA Enhanced Graphics Adaptor EGP Exterior Gateway Protocol EGP Exterior Gateway Protocol (IETF) EGSM Extended (frequency range) GSM EHF Extremely High Frequency EHP Electron-Hole Pairs EHSA Enhanced High System Availability EI Expansion Interface EIA Electronics Industry Association EIDE Enhanced Integrated Device Electronics EIGRP Enhanced Interior Gateway Routing Protocol (Cisco) EIM Errored Interval Monitored EIP Ethernet Interface Processor (Cisco) EIR Equipment Identity Register EIR Equipment Identity Register (GSM) EIR Equipment Identity/Identification Register EIR Excess Information Rate (FR) EIRP Effective Isotropic Radiated Power EIRP Effective Isotropic Radiated Power (Radio) EISA Extended Industry Standard Architecture EKTS Electronic Key Telephone Service ELAN emulated LAN (ATM) ELAP EtherTalk Link Acces Protocol (AppleTalk) ELEC Ethernet Local Exchange Carrier Electronic Switched Network ELF Extremely Low Frequency ELFEXT Equal Level Far End Crosstalk ELMI Enhanced Local Management Interface EM Element Manager EMA Electronic Mail Association EMA Enterprise Management Architecture EMBARC Electronic Mail Broadcast to a Roaming Computer EMF Electro-Magnetic Force EMG Extension Module Group EMI Electro-Magnetic Interference EML Element Management Layer EMR Exchange Message Record EMS Element Management System (Network Mgmt.) EMS Emergency Management Services EMS Event Management Service EMS Expanded Memory Specification EN Egress Node EN End Node ENFIA Exchange Network Facilities for Interstate Access ENIAC Electronic Numerical Integrator and Calculator ENQ Enquiry ENS Enterprise Network Services EO End Office EOB End of Bus (DQDB) EOC Embedded Operations Channel (SONET) EOD End of Dialing EOF End Of File EOL End Of Line EOM End of Message (DQDB, SMDS) EOT End of Transmission (BISYNC) EPD Early Packet Discard (ATM) EPG Electronic Programme Guide EPROM Erasable Programmable Read Only Memory EPS Enhanced Paging Service EPSCS Enhanced Private Switch Controlled System EPSCS Enhanced Private Switched Communications Service Equipment ER Egress Router ER Equipment Room ER Explicit Rate (ATM) ERC Easily Recognizable Code ERD Enhanced Repeat Dial service Ergonomist ERL Echo Return Loss ERM Explicit Rate Marketing ERMES Enhanced Radio Messaging System ERO European Radiocommunications Office ERP Effective Radiated Power ES-IS End System-to-Intermediate System ES Earth Station ES Echo Suppressor ES End-System (ISO) ES Errored Second ESCON Enterprise System Connection (IBM) ESD Electro-Static Discharge ESDI Enhanced Small Device Interface ESDRAM Enhanced SDRAM ESF Extended Super Frame ESFDL Extended Super Frame Data-Link ESG Enhanced Service Gateway ESI End System Identifier ESIG European SMDS Interest Group ESME External Short Message Entity ESMR Enhanced Special Mobile Radio ESMR Enhanced Specialized Mobile Radio ESMTP Extended Simple Mail Transfer Protocol ESN Electronic Serial Number ESN Emergency Service Number ESN Equipment Serial Number ESP Encapsulating Security Payload ESP End Signaling Point ESP Enhanced Service Provider(s) ESP Enhanced Service Providers ESP Extended Services Processor (Cisco) ESPRIT European Strategic Programme for Research and Development in Information Technology ESS Electronic Switching System ET Exchange Termination ETACS Extended TACS ETB End of Text Block (BISYNC) ETC Eligible Telecommunications ETC Enhanced Throughput Cellular ETC Exchange Terminal Circuit ETE End-To-End ETF Electronic Telephone Features ETN Electronic Tandem Network ETR Early Token Release (Token Ring, FDDI) ETS European Telecommunications Standard ETSI European Telecommunications Standards Institute ETX End of Text (BISYNC) EUCL End User Common Line EULA End User License Agreement EUM End User Migration EUN External Update Notification EUnet European UNIX Network EWOS European Workshop for Open Systems Exchange Carrier EXCO EXchange Central Office EXM Exit Message EXZ Excessive Zeros FA Favourite Area FABS Flexible Automated Billing System FACCH Fast ACCH (GSM) FACS Facility Assignment and Control System FAQ Frequently Asked Question FAS Frame Alignment Sequence (T-1) FAS Frame Alignment Signal FAT File Allocation Table FAT File Allocation Table (Operating Systems) FAW Frame Alignment Word FAX facsimile FB Framing Bit FB Frequency Correction Burst FBWA Fixed Broadband Wireless Access FCAPS Fault, Configuration, Accounting, Performance and Security (OAM) FCC Federal Communications Commission FCC Forward Control Channel FCCH Frequency Correction Channel (GSM) FCDR Fast CDR Handler FCFS First Come First Served FCIF Full Common Intermediate Format FCRAM Fast Cycle RAM FCS Frame Check Sequence FCS Frame Check Sequence (Data Link Protocols) FDA Food and Drug Administration FDD Frequency Division Duplex FDDI Fiber Distributed Data Interface FDDI Fiber Distributed Data Interface (ANSI) FDF Fiber Distribution Frame FDI Feeder Distribution Interface FDL Facility Data Link FDLC Fujitsu Digital Loop Carrier FDM Frequency Division Multiplexer FDM Frequency Division Multiplexer/Multiplexing FDMA Frequency Division Multiple Access FDX Full-Duplex FE Fast Ethernet FE Frame synchronization bit error Event FE Front-end FEA Federal Executive Agencies FEAC Far End Alarm and Control FEAL Fast Encryption ALgorithm FEBE-f Far End Block Error Count-fast data FEBE-i Far End Block Error Count-interleaved data FEBE Far End Block Error FEC Forward Error Correction FECC-f Forward Error Correction Count-fast data FECC-i Forward Error Correction Count-interleaved data FECC Far-End Camera Control FECN Forward Explicit Congestion Notification FECN Forward Explicit Congestion Notification (LAPF) FEH Fatal Exception Handler FEIP Fast Ethernet Interface Processor (Cisco) FELB Far End Loop Back FEP Front End Processor FEP Front End Processor (IBM) FEPS Facility and Equipment Planning System FERF Far End Receive Failure FET Field Effect Transistor FEX Foreign EXchange FEXT Far-End Cross Talk FFOL FDDI Follow-On LANs FFS For Further Study FG Feature Group FG Frame Ground FGD Feature Group D FGD Feature Group D (protocol to transmit MIN and PIC for cellular) FH-CDMA Frequency Hopping CDMA FH Fiber Hub FH Frame Handler FH Frequency Hopping FHSS Frequency Hopping Spread Spectrum FI Facility Identification FIB Forward Indicator Bit (SS7) FIBR Forward Indicator Bit Received FIBT Forward Indicator Bit to be Transmitted FIBX Forward Indicator Bit eXpected FIC Frame Identification Code FICON Fiber Connectivity FID Feature Identification code FID Field IDentifier FID Format Identification (SNA) FIFO First In First Out FIFO First In, First Out FIP FDDI Interface Processor (Cisco) FIPS Federal Information Processing Standards FIRP Federal Internetworking Requirements Panel FISU Fill-In Signal Unit (SS7) FITL Fiber In The Loop FLL Fixed Loss Loop FLM Fiber Loop Multiplexer FLTL Full Line Terminal FM Frequency Modulation FM Function Management FMC Fixed Mobile Convergence FN Fiber Node FN Frame Number (GSM) FNPRM Further Notice of Proposed Rulemaking FNS Feature Node Services FO Fiber Optics FOC Firm Order Confirmation FOD Fax On Demand FoIP Fax Over Internet Protocol FOIRL Fiber Optic Inter-Repeater Link FOT Fiber Optic Terminal FOTS Fiber Optic Transmission System FOTS Fiber Optics Transmission System FPLMTS Future Public Land Mobile Telecommunications System FPM Fast Page Mode FPP Flexible Pricing Plan FPS Fast Packet Switching FPS Framing Pattern Sequence FPU Floating Point Unit FQDN Fully Qualified Domain Name FQPCID Fully Qualified Procedure Correlation Identifier FR-PVC Frame Relay Permanent Virtual Connection FR-SSCS Frame Relay Service Specific Convergence Sub-layer FR Frame Relay FRA Fixed Radio Access FRA Fixed Radio Access (WLL) FRAC Frame Aligner Circuit FRAD Frame Relay Access Device FRAD Frame Relay Access Device (Cisco) FRAD Frame Relay Assembler/Disassembler FRAS Frame Relay Access Support (Cisco) FRASM Frame Relay Access Service Module FRD Feature Request Document FRF-LMI Frame Relay Forum-Local Management Interface FRF Frame Relay Forum FRL Facility Restriction Level FRMR Frame Reject (HDLC) FRP Fragmentation Protocol (VINES) FRS Frame Relay Service FRS Frame Relay Switch FRSS Frame Relay Switching System FRTS Frame Relay Traffic Shaping FS Feature Server FS Frame Status FSA Fiber Serving Area FSD Feature Specific Document FSDPSK Filtered Symmetric Differential Phase Shift Keying FSIP Fast Serial Interface Processor (Cisco) FSK Frequency Shift Keying FSL Flexible Service Logic FSM Finite State Machine FSMO Flexible Single-Master Operation FSN Forward Sequence Number (SS7) FSOQ Frequency Shift Offset Quadrature Modulation FSS Facility Selective Service FSS Fixed Satellite Service FSSRP Fast Simple Server Redundancy Protocol FST Fast Sequenced Transport (Cisco) FT1 Fractional T1 FTA Federal Telecommunications Act of 1996 FTAM File Transfer Access & Management FTAM File Transfer, Access and Management (ISO) FTC Fault Tolerance Controller FTE Full Time Equivalent FTP File Transfer Protocol FTP File Transfer Protocol (IETF) FTSC Federal Telecommunications Standards Committee FTTC Fiber To The Curb FTTH Fiber To The Home FTTL Fiber To The Loop FTTN Fiber To The Neighborhood FUNI Frame User-Network Interface (ATM) FUT Friendly User Trial FX Foreign Exchange FXO Foreign Exchange Office FXS Foreign Exchange Station FXS Foreign Exchange Subscriber/Station G/T Gain to Thermal noise G Giga G Giga- GAAP Generally Accepted Accounting Principles GAP Generic Access Parameter GAP Generic Access Profile (DECT) GBPS / GB/s GigaBits Per Second GBPS GigaBits Per Second GC Group Card GCAC Generic Connection Admission Control (ATM) GCD Graphic Codepoint Definition GCF Global Certification Forum GCI General Circuit Interface GCR General Configuration Register GCRA Generic Cell Rate Algorithm (ATM) GDI Generic Data interface GDOP Geometric Dilution of Precision GDP Gateway Discovery Protocol (Cisco) GE General Electric GEO Geostationary Earth Orbit GEOS Geostationary Earth Orbit Satellite(s) GERAN GSM-EDGE Radio Access Network GFC Generic Flow Control GFC Generic Flow Control (ATM) GFI General Format Identifier (X.25) GFLOPS One Billion Floating Point Operations per Second GGP Gateway to Gateway Protocol GGRF GSM Global Roaming Forum GGSN Gateway GPRS Support Node(s) GGSN Gateway GPRS Support Nodes GHZ GigaHertz GIF Graphic Interface Format GIN GSM Information Network GIO Generic Interface for Operations (SMDS) GIS Geographic Information Systems GIX Global Internet eXchange GK GateKeeper GKTMP Gatekeeper Transaction Message Protocol (Cisco) GMPCS Global Mobile Personal Communications by Satellite GMS Geostationary Meteorological Satellite GMSC Gateway Mobile Switching Center (GSM) GMSK Gaussian filtered Minimum Shift Keying GMT Greenwich Mean Team GN Generic Name GN Geographic Number (GSM - UMTS) GNS Get Nearest Server GO General Order GOB Group of Blocks GOS Grade Of Service GOSIP Government Open System(s) Interconnection Profile GP Group Processor GPPC General Purpose Power Controller GPRS General Packet Radio Service (GSM - UMTS) GPRS General(ized) Packet Radio Service/System GPRS Generalized Packet Radio Service/System GPS Global Position Satellite/System GPS Global Positioning Service/System GPS Global Positioning System GRE Generic Routing Encapsulation (Cisco) GRIN Graded-Index Fiber GRJ Geatekeeper Reject (RAS) GRQ Gatekeeper Request (RAS) GRS Group Reset Message GRX GPRS Roaming Exchange GS Gate Server GS Ground Start GS Group Separator GSA General Services Administration GSC Gateway Switching Center GSM-R GSM-Railway GSM Global Standard/System for Mobile telecommunications GSN GPRS support node GSP Global Service Provider GSS Generic Service State GSS Group Switching Subsystem GTP GPRS Tunneling Protocol GTT Global Title Translation(s) GTT Global Title Translations GTV Global Title Value GTXC Global Telephone Exchange Carrier GUI Graphical/Graphics User Interface GUI Graphics User Interface GW Gateway H Header HA High Availability HAC Hands-Free Add-On Circuit HCDS High Capacity Data Services HCDS High Capacity Digital Services HCM High Capacity Multiplexing HCS Header Check Sequence HCS Hierarchical Cell Structure HCSPR Hundred Call Seconds Per Hour HCV High Capacity Voice HDB3 High-Density Bipolar Three-Bit substitution HDLC High (level) Data Link Control HDLC High level Data Link Control HDML Handheld Device Markup Language HDOP Horizontal Dilution of Precision HDR frame HeaDeR HDS Historical Data Server HDSL High bit rate Digital Subscriber Line HDT Host Digital Terminal HDTM Half-Duplex Transmission Module (X.25) HDTV High Definition Television HDX Half-Duplex HE Head End HE Header Extension (DQDB, SMDS) HE Human Ergonomics HEC Header Error Control HEC Header Error Control (ATM) HEL Header Extension Length (DQDB, SMDS) HEX PPB Handler for External Systems HF/E Human Factors / Ergonomics HF High Frequency HF Human Factors HFC Hybrid Fiber Coax HFC Hybrid Fiber Coaxial cable HFE Hardware Forwarding Engine HFES Human Factors and Ergonomics Society HFR Hardware Failure Rate HFS Hierarchical File Storage HHDLC High-level Data Link Control (ISO) HIBCC Health Industry Business Communications Council HICAP High Capacity Digital Services HID Human Interface Device HILI Higher Layers and Internetworking (IEEE 802) HIP HSSI Interface Processor (Cisco) HIPERLAN High Performance Radio Local Access Network HIPPI High Performance Parallel Interface HIPPI HIgh performance Parallel Processing Interface HLD High Level Design HLFD High Level Functional Design HLL High Level Language HLM Heterogeneous LAN Manager HLPI Higher Layer Protocol Identifier (DQDB, SMDS) HLR Home Location Register HLR Home Location Register (GSM - UMTS) HMA High Memory Area HMAC Hash-based Message Authentication Code HMI Human-Machine Interface HMLP High-speed Multi Layer Protocol HMW High Molecular Weight HNPA Home Numbering Plan Area HO Handover HO High Order HOB Head of Bus (DQDB) HOSTID Host Identifier HP/UX HP's Version of UNIX Operating System HP Hewlett-Packard HPA High Power Amplifier HPAD Host Packet Assembler/Disassembler (BPAD) HPC High Performance Computing HPC High Probability of Completion HPCC High Performance Computing and Communications HPCS High Performance Computing Systems HPFS High Performance File System HPQLOMGC HP Lights-Out Migration Command Line HPQLOMIG HP Lights-Out Migration HPR High Performance Routing HQ Headquarters HS High Speed HSC Hierarchical Storage Controller HSCI High Speed Communications Interface (Cisco) HSCSD High Speed Circuit Switched Data HSLAN High Speed LAN HSM Hardware Security Module (SZ) HSN Hopping Sequence Number HSPSD High Speed Packet Switched Data HSRP Hot Standby Router Protocol (Cisco) HSSI High Speed Serial Interface (ANSI) HT Holding Time HTML HyperText Markup Language HTTP HyperText Transfer Protocol (IETF) HTTP Hypertext Transfer Protocol (Protocol) HTTP HyperText Transmission Protocol HTTPS HTTP Secure HTU-C HDSL Transmission Unit-Central Office HTU-R HDSL Transmission Unit-Remote HTU HDSL Transmission Unit Hz Hertz I&R Installation and Repair I/O Input and Output IA5 International Alphabet #5 (ITU-T) IAA Initial Address Acknowledgement IAB Internet Advisory Board IAB Internet Architecture Board (formerly Activities) IAC Initial Alignment Control IAC International Access Code IAC Internet Access Controler IACS Integrated Access and Crossconnect System IAD Integrated Access Device IAM Initial Address Message IAM Initial Address Message (SS7) IANA Internet Address Naming Authority IAR Initial Address Reject IAT Integrated Access Terminal IBC In-Band Control IBDN Integrated Building Distrubution Network IBO Input Back Off IC-POT Interexchange Carrier-Point of Termination IC Independent Company IC Installation Center IC Integrated Circuit IC Interexchange Carrier ICANN Internet Corporation for Assigned Names and Numbers ICB Individual Case Basis ICC Interface Controller Card ICCB Internet Control and Configuration Board ICCF Industry Carriers Compatibility Forum ICCF Interexchange Carrier Compatibility Forum ICCID Integrated Circuit Card ID (GSM - UMTS) ICD International Code Designator ICI Inter-Carrier Interface (SMDS) ICI Interexchange Carrier Interface (Bellcore) ICID Interexchange Carrier ID ICID Internet Caller IDentification service ICIP Inter-Carrier Interface Protocol ICL Inserted Connection Loss ICLID Incoming Caller Line IDentification ICM Intelligent Call Management ICMP Internet Control Message Protocol ICMP Internet Control Message Protocol (IETF) ICOT Inner City and Outstate Trunk ICP Intelligent Call Processing ICP Internet Control Protocol ICR Intelligent Call Router ICRL Indirect Certificate Revocation List (X.509) ICSC Interexchange Carrier Service Center ICSWE Interexchange Carrier Serving Wire Center ICU ISA Configuration Utility IDB Interface Description Block IDC Internet Data Center IDCP Internet Device Control Protocol IDCT Inverse Discrete Cosine Transform (DCT) IDE Integrated Device Electronics IDE Intelligent Drive Electronics IDEA International Data Encryption Algorithm IDEC Integrated Dynamic Echo Canceller (PictureTel) IDF Intermediate Distributing Frame IDF Intermediate Distributing/Distribution Frame IDI Initial Domain Identifier (ISO) IDLC Integrated Digital Loop Carrier IDN Integrated Digital Network IDN International Data Number (X.121) IDNX Integrated Digital Network Exchange IDP Initial Detection Point (GSM - UMTS) IDP Initial Domain Part IDP Internet Datagram Protocol IDPR Interdomain Policy Routing IDR Internet Detail Record IDS Information Display System (BISYNC) IDS Intrusion Detection System IDT Information Distribution Company IDT Integrated Digital Terminal IDU Interface Data Unit IE Information Element (ISDN/B-ISDN DSS) IEA International Ergonomics Association IEC InterExchange Carrier IEC International Electrotechnical Commission IEEE Institute of Electrical & Electronics Engineers IEEE Institute of Electrical and Electronics Engineers IESG Internet Engineering Steering Group IETF Internet Engineering Task Force IF Intermediate Frequency IFA IP Floating Address IFC Installed First Cost IFR Item for Resolution IFRB International Frequency Registration Board IG Interface Group IGES Initial Graphics Exchange Specification IGMP Internet Group Management Protocol IGOSS Industry/Government Open Systems Specification IGP Interior Gateway Protocol (IETF) IGRP Interior Gateway Routing Protocol (Cisco) IHL Internet Header Length (IP) IIHSO Intercompany Interconnection Held Service Order IIME Intra-network, Inter-SSS Mapping Entity IIS Internet Information Server IISO Intercompany Interconnection Service Order IIT Interactive Information Technology IKE Internet Key Exchange ILD Injection Laser Diode ILEC Incumbent Local Exchange Carrier ILEC Independent Local Exchange Carrier ILMI Interim Local Management Interface iLO Integrated Lights-Out (HP) ILP IntraLATA Presubscription IM Instant Messaging IM Intensity Modulation IMA International Multimedia Association IMA Inverse Multiplexing over ATM IMAP4 IMAP version 4 IMAP4 Internet Message Access Protocol 4 IMAP Internet Messaging Access Protocol IMD Integrated Management Display IMDB In-Memory Data Base IMEI International Mobile Equipment Identity (GSM - UMTS) IMG Industry Markets Group IML Incoming Matching Loss IML Integrated Management Log IML Integrated Management Log (HP) IMP Interface Message Processor(s) IMS Interactive Multimedia Server IMS Interface Management System IMSI International Mobile Subscriber Identity (GSM - UMTS) IMT Inter-Machine Trunk IMTC International Multimedia Teleconferencing Consortium IMTS Improved Mobile Telephone Service IMUX Intelligent Multiplexer IMUX Inverse Multiplexer IN Ingress Node IN Intelligent Network (AIN) IN Interface Network INA Information Network Architecture INA Interactive Network Adapter INAP Intelligent Network Application Part/Protocol (SS7) INB Install Busy INC Industry Numbering Committee INCRP Intelligent Network Call Routing Protocol INE Intelligent Network Element INL Internodal Link INMARSAT INternational MARitime Satellite Service INP Interim Number Portability INP Internet Nodal Processor INPA Interchangeable Numbering Plan Area INPG Industry Number Plan Guide INR Information Request Message INS Information Network System INWATS INward Wide Area Telephone Service IO Inter-Office IOC Inter-Office Channel IOCC I/O Channel Controller IOP Input/Output Processor IO