# 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 Z

#

1-ESS	x-ESS series of "Electronic Switching Systems" from AT&T/Lucent
3G	Third Generation (Mobile Network)
3GPP	Third-Generation Partnership Project
3WC	Three Way calling
4GL	Fourth-Generation Language
800 or 888	Freephone
802.x	Series of LAN standards developed by IEEE
911	Emergency telephone number in North America

# 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 Z

A

AAV	Alternative Access Vendor
ABR	Available Bit Rate
AC	Access Control, or Alternating Current, or Authentication Center (also AUC)
ACD	Automatic Call Distributor
ACE	Authentication Encryption
ACEK	Authentication Encryption Key
ACK	Acknowledgement
ACP	Access Control Point
ACRE	Authorization and Call Routing Equipment
ADM	Add-Drop Multiplexer (SDH Element)
ADPCM	Adaptive Differential Pulse Code Modulation
ADSL	Asymmetric Digital Subscriber Line
AGRAS	Air-Ground Radiotelephone Automated Service
AIOD	Automatic Identification of Outward Dialed calls
AIN	Advanced Intelligent Network (ANSI IN Standard)
A-key	Authentication key
ALI	Automatic Location Information
AM	Amplitude Modulation
AMPS	Advanced Mobile Phone System
ANI	Automatic Number Identification
ANS	Advanced Network Services
ANSI	American National Standards Institute
ANSI-41	ANSI standard for mobile management (ANSI/TIA/EIA-41)
ANT	ADSL Network Terminator
AOA	Angle of Arrival
AOL	America On Line (ISP)
API	Application Programming Interface
APPC	Advanced Program-to Program Communications (IBM SNA)
APPN	Advanced Peer-to-Peer Network (IBM SNA)
ARCnet	Attached Resource Computer Network (Datapoint)
ARDIS	Advanced Radio Data Information Service
ARP	Address Resolution Protocol
ARPA	Advanced Research Projects Agency
ARPU	Average Revenue Per User
ARPANET	ARPA Network
ARQ	Automatic Repeat Request
ARS	Automatic Route Selection
ASCII	American Standard Code for Information Interchange
ASIC	Application-Specific Integrated Circuit
ASN.1	Abstract Syntax Notation 1 (ISO)
ASP	Application Service Provider
ASR	Automatic Send Receive, Automatic Speech Recognition
AT&T	American Telephone & Telegraph
ATIS	Alliance for Telecommunications Industry Solutions (formerly ECSA)
ATM	Asynchronous Transfer Mode, Automatic Teller Machine
ATSC	Advanced Television Systems Committee
AUI	Attachment Unit Interface
AWG	American Wire Gauge
AXE 10	Series of electronic telephone exchanges from L.M. Ericsson

# 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 Z

B

B2B	Business-to-Business
B2C	Business-to-Consumer
B8ZS	Binary Eight Zero Substitution
BACP	Bandwidth Allocation Control Protocol
BBS	Bulletin Board System
Bellcore	Bell Communications Research, Inc. (Now Telcordia)
BEP	Back-End Processor
BER	Bit Error Rate
BERT	Bit Error Rate Test (or Tester)
BIOS	Basic Input-Output System
B-ISDN	Broadband ISDN
BOC	Bell Operating Company (USA)
BONDING	Bandwidth On Demand Interoperability Group
bps	bits per second
BRI	Basic Rate Interface (ISDN)
BS	Base Station
BSC	Base Station Controller, or Binary Synchronous Communications (IBM)
BSS	Base Station Sub-system (GSM)
BSS	Business Support Systems
BTS	Base Transceiver Station

# 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 Z

C

CAD	Computer-Aided Design
CAM	Computer-Aided Manufacturing
CAMEL	Customized Applications for Mobile-network Enhanced Logic (GSM/ETSI)
CAN	Campus Area Network
CANARIE	Canadian Network for Advancement of Research, Industry, Education
CAP	Competitive Access Provider
CAPS	Common ISDN API Service
CARS	Cable Antenna Relay Services
CASE	Computer-Aided Software Engineering
CATV	Cable Television or Community Antenna Television
CAVE	Cellular Authentication and Voice Encryption
CB	Citizens Band
CBR	Constant Bit Rate
CCC	Clear Channel Capability
CCCH	Common Control Channel
CCD	Charge Coupled Device
CCIR	Comité Consultatif International des Radiocommunications (now ITU-R)
CCITT	Comité Consultatif International des Télégraphes et Téléphones (now ITU-T)
CCR	Customer Controlled Reconfiguration
CCS	Common Channel Signaling
CCSS6	Common Channel Signaling System # 6
CD-R	Compact Disk-Recordable
CD-ROM	Compact Disk-Read-Only Memory
CDMA	Code Division Multiple Access
CDO	Community Dial Office
CDPD	Cellular Digital Packet Data
CDR	Call Detail Record
CENTREX	Central Office Exchange (PBX-like Service)
CEPT	Conference of European Posts and Telecommunications
CERN	Centre Européen de Recherche Nucléaire
CGSA	Cellular Geographic Service Areas
CIR	Committed Information Rate
CLASS	Custom Local Area Signaling Services
CLEC	Competitive Local Exchange Carrier
CLI	Calling Line Identification
CMA	Communications Management Association
CMIP	Common Management Information Protocol (ISO)
CMIS	Common Management Information Services (ISO)
CMISE	Common Management Information Service Element (ISO)
CMOS	Complementary Metal Oxide Semiconductors
CMRS	Commercial Mobile Radio Service
CNET	Centre National d'Études en Télécommunications (France Telecom)
CNI	Calling Number Identification
CO	Central Office
Codec	Coder/decoder
CON	Concentrator
COO	Cell of Origin
CORBA	Common Object Request Broker Architecture (OMG)
COT	Central Office Terminal
cPCI	Compact Peripheral Component Interconnect
CPE	Customer Premises Equipment
CPN	Cisco Powered Network (Ingredient Band)
CPP	Calling Party Pay
CPS	Cycles per second (Hertz)
CPU	Central Processing Unit
CRC	Cyclic Redundancy Check
CRM	Customer Relationship Management
CSA	Carrier Servicing Area
CSM	Communications Services Management
CSMA/CD	Carrier Sense Multiple Access with Collision Detection
CSR	Customer Service Representative
CSU	Channel Service Unit
CT	Cordless Telecommunications
CTI	Computer Telephony Integration
CTIA	Cellular Telecommunications Industry Association
Cu	Copper Local Loop
CUG	Closed User Groups

# 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 Z

D

D-AMPS	Digital Advanced Mobile Phone Service
DA	Destination Address
DAP	Demand Access Protocol
DARPA	Defense Advanced Research Projects Agency
DAT	Digital Audio Tape
dB	deciBel
DBMS	Database Management System
DBS	Direct Broadcast Satellite
DCE	Data Communications Equipment, or Distributed Computing Environment
DCU	Distribution and Control Unit
DDD	Direct Distance Dialing
DDS	Dataphone Digital Service
DECT	Digital Enhanced (formerly, European) Cordless Telecommunication
DES	Data Encryption Standard
DLCS	Digital Loop Carrier System
DLL	Dynamic Link Library
DLU	Digital Line Unit
DM	Distributed Management
DME	Distributed Management Environment (OSF)
DMI	Distributed Management Interface
DMS	Digital Multiplex Switch (Nortel Networks Switching Product Family DMS 100, 200, …)
DMT	Discrete Multitone
DMTF	Desktop Management Task Force
DNA	Digital Network Architecture (Digital Equipment Corporation)
DNS	Domain Name Service DoD Department of Defense (USA)
DOS	Disk Operating System
DOV	Data Over Voice
DPCM	Differential Pulse Code Modulator
DS	Digital Service, Digital Signal
DS-0	Digital Signal, Level 0 (64 kbps)
DS-1	Digital Signal, Level 1 (1.544 Mbps)
DS-1C	Digital Signal, Level 1C (3.152 Mbps)
DS-2	Digital Signal, Level 2 (6.312 Mbps)
DS-3	Digital Signal, Level 3 (44.736 Mbps)
DS-4	Digital Signal, Level 4 (274.176 Mbps)
DSI	Digital Speech Interpolation
DSL	Digital Subscriber Line
DSP	Digital Signal Processor
DSS	Decision Support System
DSU	Digital Service Unit
DTAM	Document Transfer and Manipulation (ISO)
DTE	Data Terminal Equipment
DTMF	Dual-Tone MultiFrequency
DTU	Data Transfer Unit
DTV	Digital Television
DVB	Digital Video Broadcasting
DWDM	Dense Wavelength Division Multiplexing
DXI	Data Exchange Interface

# 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 Z

E

E2E	End-to-End
E-911	Enhanced emergency telephone number (USA)
E&M	Ear and Mouth, or recEive and transMit (signaling)
E-TDMA	Expanded Time Division Multiple Access
EAI	Enterprise Application Integration
EBCDIC	Extended Binary Coded Decimal Interchange Code (IBM)
EC	European Community
ECMA	European Community Manufacturers Association
ECSA	Exchange Carrier Standards Association (now ATIS)
EDGE	Enhanced Data for GSM Evolution
EDI	Electronic Data Interchange
EEROM	Electronically Erasable Read-Only Memory
EF&I	Engineering, Furnishing and Installation
EFT	Electronic Funds Transfer
EHF	Extremely High Frequency (more than 30 GHz)
EIA	Electronic Industries Association
EIR	Equipment Identity Register
EISA	Extended Industry Standard Architecture
EMEA	Europe, Middle East & Africa (Business Region)
EML/EMS	Element Management Layer/ Element Management Service
EMS	Enhanced Messaging Services
ENS	Enhanced Network Services
EOT	End of Transmission
EPI	External Provisioning Interface
ERMES	European Radio Message System (standard for pagers)
ERP	Enterprise Resource Management
ESCON	Enterprise System Connection (IBM)
ESMR	Enhanced Specialized Mobile Radio
ETSI	European Telecommunications Standard Institute
EU	European Union

# 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 Z

F

FASB	Financial Accounting Standards Board (USA)
FAT	File Allocation Table
FC	Frame Control, or Fiber Channel
FCAPS	Fault, Configuration, Accounts, Performance, Security (ISO)
FCC	Federal Communications Commission (USA)
FCS	Frame Check Sequence
FDD	Frequency Division Duplex
FDDI	Fiber Distributed Data Interface
FDIC	Federal Deposit Insurance Corporation (USA)
FDMMA	Frequency Division Multiplexing Multiple Access
FEP	Front-End Processor
FHSS	Frequency Hopping Spread Spectrum
FIFO	First-In First-Out
FITL	Fiber In The Loop
FM	Frequency Modulation
FMS	Fraud Management System
FO	Fiber Optic
FOD	Fax on Demand
FR	Frame Relay
FRAD	Frame Relay Access Device, or Assembler/ Disassembler
FRS	Family Radio Service
FSK	Frequency-Shift Keying
FSS	Fixed Satellite System
FTAM	File Transfer, Access, and Manipulation (ISO)
FT1	Fractional T1
FTP	File Transfer Protocol (TCP/IP)
FTS	Federal Telecommunications System
FTTB	Fiber To The Building
FTTC	Fiber To The Curb
FTTK	Fibre To The Kerb
FTTH	Fiber To The Home
FWA	Fixed Wireless Access

# 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 Z

G

GAN	Global Area Network
GATT	General Agreement on Tariffs and Trade
Gb	gigabit
GB	gigabyte
GDS	Generic Digital Services
GEO	Geostationary-Earth-Orbit
GHz	gigaHertz (billions of cycles per second)
GIS	Geographic Information System
GMRS	General Mobile Radio Service
GOSIP	Government Open Systems Interconnection Profile (USA)
GPRS	General Packet Radio Service
GPS	Global Positioning System
GRX	GPRS Roaming Exchange
GSA	General Services Administration (USA)
GSM	Global System for Mobile telecommunications, or Groupe Spécial Mobile
GUI	Graphical User Interface
GVPN	Global Virtual Private Network

# 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 Z

H

H0	High-capacity ISDN channel operating at 384 kbps
H11	High-capacity ISDN channel operating at 1.536 Mbps
H323	ANSI standard for format over IP
HDLC	High-level Data Link Control (ISO)
HDSL	High-bit-rate Digital Subscriber Line
HDTV	High-Definition Television
HF	High Frequency (3 MHz to 30 MHz)
HFC	Hybrid Fiber/Coax
HIC	Head-end Interface Converter
HLR	Home Location Register
HomePNA	Home Phoneline Networking Alliance
HPPI	High-Performance Parallel Interface
HTML	HyperText Markup Language
HTTP	HyperText Transfer Protocol
HVAC	Heating, Ventilation, and Air Conditioning
Hz	Hertz (cycles per second)

# 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 Z

I

I/O	Input/Output
IA5	International Alpha Set No. 5
IAB	Internet Architecture Board
IAC	Install And Commission
IANA	Internet Assigned Numbers Authority
ICANN	Internet Corporation for Assigned Names and Numbers
ICI	Interexchange Carrier Interface
ICMP	Internet Control Message Protocol
ICR	Intelligent Call Routing
ICS	Intelligent Calling System ID Identification
IDDD	International Direct Dialing Designator
iDEN	integrated Dispatch Enhanced Network
IDPR	Interdomain Policy Routing
IEC	International Electrotechnical Commission, or InterExchange Carrier
IEEE	Institute of Electrical and Electronics Engineers
IESG	Internet Engineering Steering Group
IETF	Internet Engineering Task Force
ILEC	Incumbent Local Exchange Carrier
IM	Instant Messaging
IMAP	Internet Mail Access Protocol (IETF)
IMEI	International Mobile Equipment Identity
IMN	Intelligent Mobile Network
IMT-2000	International Mobile Telecommunications 2000 (ITU)
IMSI	International Mobile Subscriber Identity
IN	Intelligent Network
IN7	Compaq SS7 stack (previously DECss7)
INAP	Intelligent Network Application Part (IN)
INMS	Integrated Network Management System
INTELSAT	International Telecommunications Satellite Organization
I/O	Input/Output
IOC	InterOffice Channel
IOPS	Internet Operators' Providers Services
IP	Intelectual Property
IP	Intelligent Peripheral (IN)
IP	Internet Protocol (IETF)
IPN	Intelligent Peripheral Node
IPO	Initial Public Offering
IPoATM	Internet Protocol over ATM
IPR	Intellectual Property Rights
IPX	Internetwork Packet Exchange
IrDA	Infrared Data Association
IrLAN	Infrared LAN
IrLAP	Infrared Link Access Protocol
IRC	International Record Carrier
IRR	Internal Rate of Return (Financial Modelling)
IRQ	Interrupt Request
IRTF	Internet Research Task Force
IS	Information System, or Interim Standard (TIA/EIA)
IS-41	TIA/EIA Interim Standard for mobile management
ISA	Industry Standard Architecture
ISC	International Switching Center
ISDN	Integrated Services Digital Network
ISM	Industrial, Scientific, and Medical (frequency bands)
ISO	International Standards Organization
ISOC	Internet Society
ISP	Internet Service Provider
ISUP	ISDN Service User Part
IT	Information Technology
ITR	Intelligent Text Retrieval
ITT	International Telegraph and Telephone
ITT	Invitation To Tender
ITU	International Telecommunication Union
ITU-R	International Telecommunication Union-Radiocommunications
ITU-T	International Telecommunication Union-Telecommunications
IVR	Interactive Voice Response
IXC	IntereXchange Carrier (also IEC)

# 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 Z

J

JDC	Japan Digital Cellular
JIT	Just In Time
JPEG	Joint Photographic Experts Group

# 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 Z

K

KB	Kilobyte: One thousand and twenty-four bytes kbps kilo bit per second
KSR	Key Send Receive
KSU	Key Service Unit
KTS	Key Telephone System
kHz	kiloHertz (thousands of cycles per second)

# 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 Z

L

LAN	Local Area Network
LAP	Link Access Protocol (or Procedure)
LAP-B	Link Access Protocol-Balanced
LAP-D	Link Access Procedure- Digital channel (ISDN)
LAT	Local Area Transport (Digital Equipment Corporation)
LATA	Local Access and Transport Area (USA)
LBA	Location Based Advertising
LBS	Location Based Services
LCD	Liquid Crystal Display
LCN	Local Channel Number
LCR	Least Cost Routing
LD	Laser Diode
LD	Long Distance
LDC	Long Distance Carrier
LEC	Local Exchange Carrier
LED	Light-Emitting Diode
LEO	Low-Earth-Orbit
LF	Low Frequency (30 kHz to 300 kHz)
LLC	Logical Link Control
LMDS	Local Multipoint Distribution Services
LMS	Location and Monitoring Service
LRC	Longitudinal Redundancy Check
LSI	Large-Scale Integration
LU	Logical Unit (IBM)

# 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 Z

M

MB	megabyte
MAC	Media Access Control, or Move, Add, and Change
MAN	Metropolitan Area Network
MAP	Manufacturers Application Protocol (ISO, General Motors), or Mobile Applications Port
MAPI	Messaging Applications Programming Interface (Microsoft)
MAPS	Maps Application Provisioning System
MAU	Multistation Access Unit
MC	Management Center or Message Center
MCA	Micro Channel Architecture (IBM)
MCU	Multipoint Control Unit
MD	Mediation Device
MDF	Main Distribution Frame
MDN	Mobile Directory Number
MEO	Middle-Earth-Orbit
MES	Master Earth Station
MF	Mediation Function, or Medium Frequency (300 kHz to 3 MHz)
MHS	Message Handling Source MHz megahertz (millions of cycles per second)
MIB	Management Information Base
MIC	Management Integration Consortium
MILNET	Military Network (USA)
MIME	Multipurpose Internet Mail Extensions
MIN	Mobile Identification Number
MIPS	Millions of Instructions Per Second
MIS	Management Information Services, or Marketing Intelligence System
MLS	Mobile Location Services
MMDS	Multichannel, Multipoint Distribution Service
MMS	Multimedia Message Service
MO	Magneto-Optical Modem Modulator/demodulator
MOU	Minutes of Use, or Memorandum of Understanding
MPEG	Motion Picture Experts Group
MPLS	Multi Protocol Label Switching (IETF)
MPPP	Multilink Point-to-Point Protocol
MRI	Magnetic Resonance Imaging
ms	millisecond (thousandth of a second)
MS	Mobile Station
MSC	Mobile Switching Center
MSN	Microsoft Network
MSRN	Mobile Station Roaming Number
MSS	Mobile Satellite Service
MTBF	Mean Time Between Failure
MTP	Message Transfer Part (IN)
MTS	Message Telecommunications Service
MTSO	Mobile Telephone Switching Office
MTTR	Mean Time To Repair
MTU	Maximum Transmission Unit
MVDS	Microwave Video Distribution System
MVPRP	Multivendor Problem Resolution Process

# 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 Z

N

N-AMPS	Narrowband Advanced Mobile Phone Service
NAFTA	North American Free Trade Agreement
NAK	Negative Acknowledgement
NAM	Numeric Assignment Module
NAP	Network Access Point
NAS	Network Attached Storage
NATA	North American Telecommunications Allocation
NAU	Network Addressable Unit (IBM)
NBS	National Bureau of Standards
NC	Network Computer
NCC	Network Control Center
NCP	Network Control Program (IBM SNA), or Network Control Point
NE	Network Element
NEF	Network Element Function
NEBS	New Equipment Building Specifications
NECA	National Exchange Carrier Association
NetBIOS	Network Basic Input-Output System (Microsoft)
NFS	Network File System (or Server)
NIC	Network Interface Card, or Network Information Center (Internet Registry)
NiCad	Nickel Cadmium
NiMH	Nickel-Metal Hydride
NIST	National Institute of Standards and Technology
NIU	Network Interface Unit
NLM	NetWare Loadable Module (Novell)
nm	nanometer
NM	Network Manager
NMC	Network Management Center
NMC	Nortel Matra Cellular
NMF	Network Management Forum (now TMF)
NML/NMS	Network Management Layer/Network Management Service
NMS	NetWare Management System (Novell)
NNM	Network Node Manager (Hewlett-Packard)
NOC	Network Operations Center
NOS	Network Operating System
NPI	New Product Introduction
NREN	National Research and Education Network (USA)
NRZ	Non-Return to Zero
NSA	National Security Agency
NSF	National Science Foundation (USA)
NSK	Non-Stop Kernel (Compaq)
NSS	Network Switching Sub-system (GSM)
NSSG	Network Solutions and Service Group (Nortel)
NT	Network Termination, or New Technology, also Windows NT (Microsoft)
NTE	Network Terminating Equipment
NTSA	Networking Technical Support Alliance
NTSC	National Television Standards Committee
NTU	Network Termination Unit

# 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 Z

O

OA&M	Operations, Administration and Maintenance
OAM&P	Operations, Administration, Maintenance and Provisioning
OC	Optical Carrier
OC-1	Optical Carrier Signal, Level 1 (51.84 Mbps)
OC-3	Optical Carrier Signal, Level 3 (155.52 Mbps)
OC-9	Optical Carrier Signal, Level 9 (466.56 Mbps)
OC-12	Optical Carrier Signal, Level 12 (622.08 Mbps)
OC-18	Optical Carrier Signal, Level 18 (933.12 Mbps)
OC-24	Optical Carrier Signal, Level 24 (1.244 Gbps)
OC-36	Optical Carrier Signal, Level 36 (1.866 Gbps)
OC-48	Optical Carrier Signal, Level 48 (2.488 Gbps)
OC-96	Optical Carrier Signal, Level 96 (4.976 Gbps)
OC-192	Optical Carrier Signal, Level 192 (9.952 Gbps)
OC-256	Optical Carrier Signal, Level 256 (13.271 Gbps)
OCR	Optical Character Recognition
ODBC	Open Database Connectivity (Microsoft)
ODS	Operational Data Store
OEM	Original Equipment Manufacturer
OLAP	Online Analytical Processing
OLE	Object Linking and Embedding (Microsoft)
OMA	Object Management Architecture
OMA	Open Mobile Alliance
OMC	Operations and Maintenance Centre (GSM)
OMF	Object Management Framework
OMG	Object Management Group
OOP	Object-Oriented Programming
ORB	Object Request Broker
OS	Operating System
OS/2	Operating System/2 (IBM)
OSF	Open Software Foundation
OSI	Open Systems Interconnection (ISO), or Objective Systems Integrator
OSP	OutSide Plant
OSPF	Open Shortest Path First
OSS	Operations Support Systems
OTA	Over The Air Activation
OTD	Open Terminal Directive (European Union)

# 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 Z

P

P2P	Person-to-Person
PABX	Private Automatic Branch eXchange
PACS	Personal Access Communications System
PAD	Packet Assembler-Disassemble
PAL	Phase Alternating by Line
PAM	Pulse Amplitude Modulation
PAN	Personal Area Network
PAP	Password Authentication Protocol
PBX	Private Branch eXchange
PC	Personal Computer
PCB	Printed Circuit Board
PCI	Peripheral Component Interconnect
PCIA	Personal Communications Industry Association
PCM	Pulse Code Modulation
PCMCIA	Personal Computer Memory Card Industry Association
PCN	Personal Communications Networks
PCS	Personal Communications Services
PDA	Personal Digital Assistant
PDC	Personal Digital Cellular (Japan)
PDE	Positioning Determination Entity
PDH	Plesiochronous Digital Hierarchy
PDN	Packet Data Network or Public Data Network
PDU	Protocol Data Unit
PM	Phase Modulation
PHY	Physical Layer
PIM	Personal Information Manager
PIN	Personal Identification Number, or Positive-Intrinsic-Negative
PLMN	Public Land Mobile Network
PMD	Physical Media-Dependent
PnP	Plug-and-Play
POP	Point Of Presence
PoS	Point Of Sale
POTS	Plain Old Telephone Service
PPC	Pay-Per-Call
PPP	Point-to-Point Protocol
PPV	Pay-Per-View
PRCS	Philips Radio Communications Systems
PRI	Primary Rate Interface (ISDN)
PROM	Programmable Read-Only Memory
PSN	Packet-Switched Network
PSTN	Public Switched Telephone Network
PSK	Phase Shift Keying
PT	Payload Type
PTT	Post, Telegraph and Telecommunications (Government Departments)
PU	Physical Unit (IBM SNA)
PUC	Public Utility Commission (USA)
PVC	Permanent Virtual Circuit
PVN	Private Virtual Network

# 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 Z

Q

Q3	Network Management Interface (ITU-T)
QA	Quality Assurance
QEDI	Quod Erat Demonstrandum
QoS	Quality of Service

# 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 Z

R

RACE	Research for Advanced Communications in Europe
RAID	Redundant Array of Inexpensive Disks
RAM	Random Access Memory
RBES	Rule-Based Expert Systems
RBOC	Regional Bell Operating Company (USA)
RCU	Remote Control Unit
RDBMS	Relational Database Management System
RDSS	Radio Determination Satellite Service
RF	Radio Frequency
RFC	Request For Comment (IETF)
RFI	Radio Frequency Interference, or Request For Information
RFP	Request For Proposal
RFQ	Request for Quotation
RIP	Routing Information Protocol
RISC	Reduced Instruction Set Computing
RJE	Remote Job Entry
RMON	Remote Monitoring
ROI	Return On Investment
ROM	Read-Only Memory
RPC	Remote Procedure Call
RSI	Repetative Strain Injury
RSVP	Resource ReSerVation Protocol (IETF)
RT	Remote Terminal
RTU	Right To Use
RX	Receive

# 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 Z

S

SA	Source Address
SAA	Systems Application Architecture (IBM)
SAN	Storage Area Network or System Area Network (Himalaya)
SC	Standards Committee (ISO)
SCCP	Signaling Connection Control Point (IN)
SCE	Service Creation Environment (IN)
SCP	Service Control Point (IBM-SNA)
SCSI	Small Computer Systems Interface
SDH	Synchronous Digital Hierarchy
SDLC	Synchronous Data Link Control (IBM)
SDN	Software-Defined Network (AT&T)
SDSL	Symmetrical Digital Subscriber Line
SHF	Super High Frequency (3 GHz to 30 GHz)
S-HTTP	Service Hypertext Transport Protocol
SIM	Subscriber Identification Module
SIP	Session Initiation Protocol (IETF)
SKU	Stock-Keeping Unit
SLIC	Subscriber Loop Interface Circuit
SLIP	Serial Line Internet Protocol (IETF)
SMDS	Switched Multimegabit Data Services
SML/SMS	Service Management Layer/Service Management Service
SMR	Specialized Mobile Radio
SMS	Service Management System
SMS	Short Message Service
SMSC	Short Message Service Center
SMT	Station Management
SMTP	Simple Mail Transfer Protocol (IETF)
SN	Switching Network or Station Number
SNA	Systems Network Architecture (IBM)
SNI	Subscriber Network Interface
SNMP	Simple Network Management Protocol
SONET	Synchronous Optical Network (ANSI)
SP	Service Provider
SPA	Software Publishers Association
SPX	Sequenced Packet Exchange (Novell)
SQL	Structured Query Language
SS	Switching System
SS#7	Signaling System # 7 (ITU-T)
SS7	Signaling System 7 (ANSI)
SSCP	System Services Control Point (IBM)
SSL	Secure Sockets Layer (IETF)
SSP	Service Switching Point (IN)
STDM	Statistical Time Division Multiplexing
STM	Synchronous Transfer Mode
STP	Shielded Twisted-Pair, or Signal Transfer Point (IN)
STX	Start of Transmission
SUBT	Subscriber Terminal
SVC	Switched Virtual Circuit
S x S	Step-by-Step
SYNTRAN	Synchronous Transmission

# 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 Z

T

T-Carrier	Trunk Carrier
T1	Transmission service at the DS1 rate of 1.544 Mbps
T2R	Trusted Transaction Roaming
T3	Transmission service at the DS3 rate of 44.736 Mbps
TAG	Technical Advisory Group
TAPI	Telephony Application Programming Interface (Microsoft)
TB	terabyte (trillion bytes)
Tbps	terabit per second
TCAP	Transaction Capabilities Application Part (IN)
TCP	Transmission Control Protocol (IETF)
TCP/IP	Transmission Control Protocol /Internet Protocol (IETF)
TDD	Time Division Duplexing
TDM	Time Division Multiplexer
TDMA	Time Division Multiple Access
TDOA	Time Difference of Arrival
TeMIP	Telecommunications Management Information Platform (Compaq)
TETRA	Trans-European Trunked Radio Access (ETSI)
TIA	Telecommunications Industry Association
TINA	Telecommunications Information Networking Architecture
TL1	Transaction Language 1
TLS	Transport Layer Security (IETF)
TMF	Telecommunications Management Forum
TMN	Telecommunications Management Network
TO	Tandem Office or Toll Office
TO	Telecommunications Operator
TOA	Time of Arrival
TQM	Total Quality Management
TRS	Telecommunications Relay Services
TSAPI	Telephony Services Application Programming Interface (Novell)
TSI	Time Slot Interchange
TTY	TeleType
TV	Television
TWX	Teletypewriter Exchange (also known as telex)
TX	Transmit

# 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 Z

U

UART	Universal Asynchronous Receiver/Transmitter
UBR	Unspecified Bit Rate
UBC	Utility Based Computing
UDP	User Datagram Protocol (IETF)
UHF	Ultra High Frequency (300MHz to 3 GHz)
UMS	Universal Messaging System
UMTS	Universal Mobile Telecommunications System (ETSI)
UN	United Nations
UNI	User-Network Interface
UPS	Uninterruptible Power Supply
URL	Universal Resource Locator (WWW)
USF	Universal Server Farm (IBM)
UTP	Unshielded Twisted - Pair
UTRA	Universal Terrestrial Radio Access

# 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 Z

V

VAN	Value-Added Network
VAR	Value-Added Reseller
VBR	Variable Bit Rate
VC	Virtual Circuit
VCR	Videocassette Recorder
VDSL	Very high-speed Digital Subscriber Line
VF	Voice Frequency
VG	Voice Grade
VHF	Very High Frequency (30 MHz to 300 MHz)
VLF	Very Low Frequency (less than 30 kHz)
VLR	Visitor Location Register
VLSI	Very Large-Scale Integration
VM	Virtual Machine (IBM)
VMS	Virtual Machine System (Digital Equipment Corporation)
VOD	Video On Demand
VoIP	Voice over IP
VPN	Virtual Private Network
VRC	Virtual Redundancy Check
VSAT	Very Small-Aperture Terminal
VT	Virtual Terminal
VTAM	Virtual Telecommunications Access Method (IBM SNA)

# 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 Z

W

W3C	World Wide Web Consortium (also WWW3)
WACS	Wireless Access Communications System
WAE	Wireless Application Environment
WAN	Wide Area Network
WAP	Wireless Application Protocol
WATS	Wide Area Telecommunications Service
W-CDMA	Wideband - Code Division Multiple Access
WCS	Wireless Communications Service
WDM	Wavelength Division Multiplexing
WDP	Wireless Datagram Protocol
WG	Working Group
WGS	Worldwide Geodesic System
WYSIWYG	What You See Is What You Get
WLAN	Wireless Local Area Network
WLL	Wireless Local Loop
WLS	Wireless Location Services (SignalSoft)
WML	Wireless Markup Language
WNT	Windows NT (Microsoft)
WORM	Write Once Read Many
WS	Workstation
WSF	Workstation Function
WSP	Wireless Session Protocol
WTA	Wireless Telephony Application
WTLS	Wireless Transport Layer Security
WTO	World Trade Organization
WTP	Wireless Transaction Protocol
WWAN	Wireless Wide Area Network
WWW	World Wide Web
WWW3	World Wide Web Consortium (also W3C)

# 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 Z

X

X25	A Packet Switching Protocol
X-Bar	Crossbar telephone exchange
XC	Cross-Connect
xDSL	"generic" Digital Subscriber Line
XML	Extensible Markup Language
XNS	Xerox Network System (Xerox Corporation)

# 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 Z

Y

Y2K

Year 2000

# 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 Z

Z

ZIP	Zone Improvement Program (geographic codes/ USA)
ZLE	Zero Latency Enterprise (Compaq)

The above is offered as a guide only. All trademarks acknowledged.
© 2002 mob1le.com