-S-
S&R	Segmentation and Re-assembly
S/ATT	Satellite Analog Tie Trunk (TIA-646-B)
S/DTT	Satellite Digital Tie Trunk (TIA-646-B)
S/MIME	Secure / Multipurpose Internet Mail Extensions
S/N	Signal-to-Noise
S/T	Logical interface between xTU-R and user terminal equipment
S/W	Software
SA1	Systems Aspects - Services (3GPP Committee)
SAA-AMS	Service Aspects and Applications - Audio/Visual Multimedia Services
SAAC	Syntax-Based Adaptive Arithmetic Coding
SABM	Set Asynchronous Balanced Mode
SABME	Set Asynchronous Balanced Mode Extended
SABT	Simplified ABT
SAC	Service Access Code
SAC	Subscriber Access Control
SAC	Syntax-based Arithmetic Coding
SACCH	Slow Associated Control Channel
SAD	Sum of Absolute Differences
SAE	Society of Automotive Engineers
SAFE	SeAmless, Fixed-overhead Efficient (framing)
SAFER	Secure and Fast Encryption Routine
SAGE	Security Algorithms Group of Experts
SAID	Serving Area ID
SAM	Synchronous Access Mode (V.80)
SAMP	Simple Audio Multiplexing Protocol
SAMPS	System Assisted Mobile Positioning through Satellite (TDMA Third Generation Wireless)
SANC	Signaling Area Network Code
SAP	Segmentation Application Part
SAP	Service Access Point
SAP	System Application Procedure
SAPI	Service Access Point Identifier
SAR	Segmentation And Re-assembly
SAR	Specific Absorption Rate
SAS	Smart Antenna Savvy
SAS	Subscriber Alerting Signal
SASET	Secure Audio SET
SAT	Satellite
SAT	Satellite ATM
SATN	Signal Attenuation
SAVD	Simultaneous or Alternating Voice Data
SBC	Southern Building Code
S-BCCH	Short Message Service Broadcast Control Channel
SBE	Single Byte Extension
SBI	Sub-Bitstream Indicators
SBID	Stuff Bit ID
SBM	Single Bitmap
SBM	Subnet Bandwidth Manager
SBSD	Supplementary and Bearer Service Description (T1S1)
SC	Service Capability
SC	Service Control
SC	Special Committee (ETSI)
SC	Spectral Compatibility
SC	Steering Committee
SC	Subscriber Confidentiality
SC	Type of commercial fiber optic connector (Push-Pull)
SCA	Selective Call Acceptance
SCaps	Capabilities with Sub-fields
SCC	Standards Coordinating Committee (IEEE)
SCC	Standards Council of Canada
SCCC	Serial Concatenated Convolutional Code
SCCH	Single Cell Control Channel
SCCP	Signaling Connection Control Part (SS7)
SCD	Service Capability Definition
S-CDMA	Synchronous CDMA
SCELP	Spike Code Excited Linear Prediction
SCF	Service Control Function
SCF	Shared Control with Feedback
SCF	Supervisory and Control Function
SCF	Synchronization and Convergence Function
SCF	System Communication Function
SCM	Single-Carrier Modulation
SCM	Station Class Mark
SCM	Sub-Carrier Multiplexing
SCN	Switched Circuit Network
SCOT	Steering Committee on Telecommunications
SCP	Service Control Point
SCPS	Authorized Call Priority Service
SCR	Selective Call Rejection
SCSA	Signal Computing System Architecture
SCSC	SubCommittee on Standards and Conformance (APEC)
SCSI	Small Computer System Interface
SCT	Strathclyde Compression Transform
SCT	Simple Control Transmission Protocol
SCT	Mexican Ministry of Communications and Transports
SCTE	Society of Cable Television Engineers (US)
ScTP	Screened Twisted Pair
SCTP	Stream Control Transmission Protocol
SCV	Specialized Codec VBR
SD	Spectral Data
SD	Super Domain
SDB	Switched Digital Broadcast
SDC	Supplier's Declaration of Conformity (also SDOC)
SDCC	Supplementary Digital Color Code
SDCCH	Standalone Dedicated Control Channel
SDD	Stutter Dialing Device
SDF	System Directory Function
SDH	Synchronous Digital Hierarchy
SDK	Software Development Kit
SDL	Structure Description Language
SDMT	Synchronized DMT
SDO	Standards Development Organization
SDoC	Suppliers Declaration of Conformity (also SDC)
SDP	Session Description Protocol
SDPng	SDP Next Generation
SDR	Sequence Determined Redundancy
SDSAF	Switched Digital Services Applications Forum
SDSL	Simultaneous DSL
SDSL	Symmetrical high bit rate Digital Subscriber Line
SDSS	Server Display And Script Services
SDT	Stutter Dial Tone
SDTV	Standard Definition Television
SDU	Service Data Unit
SE	Synchronous Editing
SEAD	Software Encryption Algorithm for Data Services
SEBCH	Systematic Extended Bose, Chaudhuri, and Hocquengham
SEC	ETSI Security Technical Committee
SECOFI	Mexican Ministry of Commerce and Industrial Development
SEI	Supplemental Enhancement Information
SELT	Single-Ended Loop Testing
SELV	Low Voltage associated with digital circuits (IEC 950)
SEP	Selective Polling (T.30)
SERVNOT	Service Notification
SES	Severely Errored Second
SES	Standards Engineering Society
SET	Simple Endpoint Types
SF	Single Frequency
SF	Superframe
SF	Synchronization Flag
SfDLy	Superframe reconfiguration Delay number (Q4/15)
SFF	Small Form Factor
SFlgSf	Synch Flag Superframe number (Q4/15)
SFR	Special Function Registers
SG	Signaling Gateway
SG	Starter Group (ETSI)
SG	Study Group (ITU)
SGCI	Simple Gateway Control Interface
SGCP	Simple Gateway Control Protocol
SGFS	Special Group for Functional Standards
SGMM	MultiMedia Study Group
SGSN	Serving GPRS Support Node
SHA	Secure Hash Algorithm
SHDSL	Single-line High Speed DSL
SHO	Soft Handoff
SHTU-R	SHDSL Handshake Transceiver Unit - Remote
SI	Sensitivity Information
SI	Signaling Intelligence
SI	Still Image
SIA	Security Industry Association
SIA	Semiconductor Industry Association
SID	Send Identifier
SID	Silence Insertion Descriptor
SID	System Identification
SIF	Standard Interchange Format
SIG	Special Interest Group
SIGTRAN	Signaling transport (IETF)
SIM	Subscriber Identity Module
SIMD	Single-Instruction, Multiple Data
SIN	System Identification Network
SIO	Scientific or Industrial Organization (ITU member)
SIP	Session Initiation Protocol (IETF)
SIPPING	Session Initiation Protocol Project INvestiGation (IETF WG)
SIPTEL	Session Initiation Profile for Internet Telephony, an IETF BoF group, which was a precurser to the IETF Working Group iptel (IP Telephony)
SIR	Signal to Interference Ratio
SIRD	Service Independent Requirements Definition
SIT	Special Information Tone
SIU	Subscriber Interface Unit
SLA	Service Level Agreement
SLB	Sequential Link Bring-up (V.MoIP)
SLC	Subscriber Loop Carrier
SLC	Start of Layer Data
SLD	Second Level Domain
SLE	Screen List Editing
SLER	Signal to Listener Echo Ratio
SLIC	Subscriber Line Integrated Circuit
SLIM	Simple Legislation for the Single Market
SLP	Service Location Protocol
SLR	Send Loudness Rating
SM	Service Management
SM	Single Mode
SM	Spectrum Management
SMALL	Short Multiplexed AAL
SMATV	Satellite Master Antenna Television
SMC	Spectrum Management Class
SMD	Short Message Delivery
SMDB	Short Message Delivery Broadcast
SMDBACK	Short Message Delivery Backward
SMDFWD	Short Message Delivery Forward
SMDM	Short Message Delivery Multipoint Bearer Service
SMDPP	Short Message Delivery Point-to-Point Bearer Service
SMDS	Switched Multi-megabit Data Service
SME	Short Message Entity
SME	Signaling Message Encryption
SME	Small-to-Medium sized Enterprises
SME	Subject Matter Expert
SMEKEY	Short Message Encryption Key
SMG	Special Mobile Group
SMI	Structure of Management Information
SMM	Spectrum Management Methodology
SMMI	Single Man Machine Interface
SMP	Simple Multiplexing Protocol
SMPTE	Society of Motion Picture and Television Engineers
SMR	Specialized Mobile Radio
SMS	Service Management System
SMS	Short Message Service
SMSA	Standard Metropolitan Statistical Area
SM-SC	Short Message Service Center
SMSC	Short Message Service Center
SMSC	SMS-call
SMSREQ	Short Message Service Request
S-MTA	Standalone MTA
SMTP	Simple Mail Transfer Protocol
SMV	Selectable Mode Vocoder
SN	Scaling Number
SN	Service Node
SNA	Synchronous Network Architecture
SNAP	Sub Network Access Protocol
SNDCP	Sub Network Dependent Convergence Protocol
SNHC	Synthetic-Natural Hybrid Coding
SNI	Service Node Interface
SNI	SMS Notification Indicator
SNI	Standard Network Interface
SNMP	Simple Network Management Protocol (IETF)
SNR-LP	SNR scalable coding with Leaky Prediction
SNR	Signal to Noise Ratio
SNRM	Signal to Noise Ratio Margin (G.dmt.bis)
SOA	Semiconductor Optical Amplifier
SOAP	Simple Object Access Protocol (IETF)
SOC	System Operator Code
SOHO	Small Office Home Office
SOI	Start of Image
SOM	Self-Organizing Multicast
SONET	Synchronous Optical Network
SOP	Standard Operating Procedure
SOS	Speech Option Selection
SOT	Send Only Terminal
SOVA	Soft Output Viterbi Algorithm
SP	Service Provider
SP	Simple Profile
SP	Standards Proposal (TIA Industry Ballot)
SP	Study Point (ETSI)
SP	Switchable-P [frames]
SPA	Service Provider Access
SPAC	Service Provider Action Council (DSL Forum)
SPACH	Short Message Service, Paging Channel and Access Response Channel
SPAI	Service Provider Access Interfaces
SPAN	Services and Protocols for Advanced Networks (ETSI TC)
SPAR	Service Provider Access Requirements (ETSI SPAN)
S-PCN	Satellite Personal Communications Network
S-PDU	Supervisory PDU
SPH	Service Profile at the Home location
spi	spots per inch
SPI	Standard Programmatic Interface
SPIFF	Still Picture Interchange File Format
SPINA	Subscriber Personal Identification Number Access
SPINI	Subscriber Personal Identification Number Intercept
SPC	Single Parity Check
SPC	System Programming Code
SPIRITS	Service in the PSTN/IN Requesting InTernet Service (IETF)
SPL	Sound Pressure Level
SPNE	Signal Processing Network Equipment
SPnP	Secure Plug and Play
SpoA	Service point of Access (TIPHON)
S-PRBS	Single cycle - Pseudo Random Bit Sequence
SPRT	Simple Packet Relay Transport
SPS	Signaling Protocols and Switching
SPS	Signaling Protocol And System Technical Committee (ETSI)
SPS5 SPC	Signaling, Protocols and Switching Stored Program Controller (ETSI)
SPTT	Signal Processing Transmission Terminals
SPV	Service Profile at the Visited location
S-PVC	Soft-Permanent Virtual Circuit
SPVC	Switched Permanent Virtual Circuit
SPWG	Service Provider-focused Working Group (Trilateral)
SQ	Scalar Quantization
SQCIF	Sub-Quarter Common Intermediate Format
SQEG	Speech Quality Expert Group (ITU)
SQL	Structured Query Language
S/R	Suspend/Resume
SR	Special Report (Telcordia)
SRA	Seamless Rate Adaptation
SRC	Source
SRC	Strategic Review Committee (ETSI)
SRD	Standards Requirements Document
SRDB	Selective Routing Data Base
SREJ	Selective Reject
SRF	Service Resource Function
sRGB	Standard RGB (Red Green Blue)
SRL	Secure Radio Link
SRL	Software Release Letter
SRL	Structural Return Loss
SRM	Standards Related Matters
SRP	Scalable Resource reservation Protocol
SRP	Server Requester Protocol
SRTP	Secure Real-time Transport Protocol
SRTS	Synchronous Residual Time Stamp
SRU	Signal Regenerator Unit
SRU-R	Signal Regenerator Unit - Remote
SS	Slice Structured
SS	Steady State
SS	Supplementary Services
SS#5	Signaling System 5
SS#7, SS7	Signaling System 7
SS-CD	Supplementary Services Call Deflection
SS-CFB	Supplementary Services Call Forwarding Busy
SS-CFNR	Supplementary Services Call Forwarding No Reply
SS-CFU	Supplementary Services Call Forwarding Unconditional
SS-CI	Supplementary Service - Call Intrusion
SSCOP	Service Specific Connecction Oriented Protocol
SSCQE	Single Stimulus Continuous Quality Evaluation
SSCS	Service Specific Convergence Sublayer
SSD	Shared Secret Data
SSDSL	Synchronized Symmetric Digital Subscriber Line
SSE	State Signaling Event
SSE	Sum of Squared Error
SSF	Service Switching Function
SSFP	Service Specific Face Plate
SSG	Service Specification Group
SSG	Special Study Group (ITU)
SSI	Signal Strength Indicator
SSL	Secure Sockets Layer
SS-MCM	Supplementary Services - Message Center Monitoring
SS-MID	Supplementary Services - Mailbox Identification
SSN	Sub-System Number
SSO	Speech Service Option
SSOVP	Solid State Primary Protectors
SSP	Service Switching Point
SSPR	System Selection for Preferred Roaming
SSRC	Synchronization Source (IETF RFC 1889, RTP)
ST	Type of commercial fiber optic connector (Bayonet)
STANAG	NATO Standardization Agreement
STAG	Security Techniques Advisory Group
STB	Set Top Box
STC	Sub-Technical Committee (ETSI)
STCX	Single Transcompression
STD	Simplified Trellis Decoder
STDT	Stutter Dial Tone
STE	Secure Terminal Equipment
STF	Specialist Task Force (ETSI)
STG	Special Task Group
STG	Special Topic Group
STI	Service Transport Interface
STIT	IEEE Subcommittee on Telephone Instrument Testing
STL	Software Tool Library
STM	Synchronous Transmission Mode
STMR	Sidetone Masking Rating
STN	Switched Telephone Network
STP	Set of Transmission Parameters (TM6)
STP	Shielded Twisted Pair
STP	Signaling Transfer Point
STP	Standards Technical Panel
STQ	Speech Transmission Quality (ETSI TC)
STRE	Side-Tone Reference Equipment
STU	Secure Terminal Unit
STU	SHDSL Transceiver Unit
STU-C	SHDSL Transceiver Unit - Central office end
STU-R	SHDSL Transceiver Unit - Remote Terminal End
STU-III	Secure Terminal Unit - III
STS	Short Term Stationary
SU	Subscriber Units
SUB	Sub-address (T.30)
SUD	Single Use Device
SUR	Survivability
SVB	Switched Video Broadcast
SVC	Switched Virtual Circuit
SVD	Simultaneous Voice Data
SVF	Simultaneous Voice and Facsimile
SW	Software
SWELP	Switched Excited Linear Predictive
SWG	Sub-Working Group
SWP	Standardization Work Plan
sYCC	The YCbCr style of sRGB color space under development as IEC 61966-2-1
-T-
T&E	Technical & Engineering Committee (Telocator)
T&I	Testing & Interoperability (DSL Forum Working Group)
T&IWG	Testing & Interoperability Working Group (ADSL Forum)
T&R	Tip and Ring
TA	Technical Assembly
TA	Terminal Adapter
TA	Transmit Additional information
TAAB	Technical Ad hoc Advisory Board
TAAC	Telecommunications Advisory Committee
TAB	Tone above Band
TABD	Trans-Atlantic Business Dialog
TAC	Terminal-Aggregator Communication
TAC	Terminal Attachment Council
TACS	Total Access Communications Systems
TAF	Terminal Adoption Function
TAG	Technical Advisory Group
TAP	Traditional Approval Process (ITU, via Resolution 1)
TAP	Two-step Approval Process (ETSI)
TAPAC	Terminal Attachment Program Advisory Committee
TAPI	Telephony API
TASA	Telecommunications Access System Act
TAWG	Terminal Attachment Working Group
TB	Technical Body (ETSI)
TB	Turbo Block
TBB	Telecommunications Bonding Backbone
TBCD	Telephony Binary Coded Decimal
TBD	To be Determined
TBG	Technical Basis for Globalization
TBH	Technical Basis for Harmonized conformance
TBI	Ten Bit Interface
TBR	Technical Basis for Regulation (ETSI)
TBRL	Terminal balance return loss
TC	Technical Committee
TC	Telecommunications Closet
TC	Test Case
TC	Transaction Capabilities
TC	Transmission Convergence layer
TC	Trellis Coded
TC	Turbo Convolutional
TCAM	Telecommunication Conformity Assessment and Market Surveillance Committee (ETSI)
TCAP	Transaction Capabilities Application Part
TC AT	Technical Committee Access and Terminals (ETSI)
TCB	Telecommunications Certification Bodies
TCBC	Telecommunications Certification Bodies Council
TCC	Technical Correlating Committee (NEC)
TCC	Borland Turbo C++ Compiler
TC-ERM	ETSI Technical Committee on EMC and Radio spectrum Matters
TCF	Training Check (T.30)
TCH	Transparent Circuit Handling
TC HF	Technical Committee Human Factor (ETSI)
TCIF	Telecommunications Industry Forum (ATIS)
TCL	Transverse Conversion Loss
TCLw	Terminal Coupling Loss weighted
TCM	Time Compression Multiplex
TCM	Trellis Coded Modulation
TCM-ISDN	Time Compression Multiplexed ISDN
TC-NA	ETSI Technical Committee on Network Aspects
TCOEF	Transform Coefficient
TCON	Telenor Research's error concealment decoder
T-CONT	Traffic Container (G.983.dba)
TCP	Terminal Connection Point
TCP	Transmission Control Protocol
TCPA	Telephone Consumer Protection Act (1991)
TC-PAM	Trellis Coded Pulse Amplitude Modulation
TCP/IP	Transmission Control Protocol/Internet Protocol (IETF)
TC SP	Technical Committee Speech Processing
TC-SPS	ETSI Technical Committee on Signaling Protocol and System
TC-TM	Technical Committees on Transmission and Multiplexing
TCR-TR	Technical Committee Report-Technical Report
TCTL	Tranverse Conversion Transfer Loss
TCX	Trans-Compression
TD	Temporary Document (ITU et al)
TDD	Task Data Descriptions (T.611 e-mail)
TDD	Telecommunications Devices for the Deaf
TDD	Time Division Duplexing
TDF	Transportable Document Format
TDM	Time Division Multiplex
TDMA	Time Division Multiple Access
TDOA	Time Difference of Arrival
TDSO	Test Data Service Option (cdma2000)
TE	Terminal Equipment (ETSI TC)
TE	Traffic Engineering
TE2	Cellular User's Terminal Equipment
TEC-LA	Telecommunications and Electronic Consortium for Latin America
TEDPA	Telecommunications Equipment Distribution Program Association (www.tedpa.org)
TEL	Telephony (APEC WG)
TELR	Talker Echo Loudness Rating
TEM	TE Management Meeting
TEM	Transverse Electro Magnetic
TEN	Trans-European Networks
TEN-Telecom	Trans-European Telecommunications Networks
TEP	Talk Echo Protection
TEQ	Time Domain Equalizer
TES	Telecommunication Equipment Safety
TETRA	Trans European Trunked RAdio
TF	Task Force (IEEE)
TFIG	Task Force Implementation Group
TFO	Tandem Free Operation
TFTP	Trivial File Transfer Protocol (RFC 1350)
TG	Task Group
TGB	Telecommunications Grounding Busbar
TGCP	Trunking Gateway Control Protocol
T-H	Tomlinson-Harashima (precoding)
THD	Total Harmonic Distortion
THL	TransHybrid Loss
THP	Tomlinson-Harashima Precoding
TI	Traffic Information
TIA	Telecommunications Industry Association
TICS	Transport Information and Control Systems
TIES	Telecom Information Exchange Services (ITU)
TIES	Time Independent Escape Sequence
TIFF	Tagged Image File Format
TIFF-F	Tagged Image File Format-Fax
TIFF-FX	Tagged Image File Format-Fax (RFC 2301)
TIGIN	Transport Network Equipment for Interconnecting GSTN and IP Networks (ITU-T G.799.1)
TILU	Telecommunications Industry Liaison Unit (FBI)
TIMS	Transmission Impairment Measurement System
TINA	Telecommunications Information Networking Architecture
TIP	Transport and Internetworking Package
TIPIA	TIPHON IP telephony Implementation Agreement
TIPHON	Telecommunications and Internet Protocol Harmonization Over Networks (ETSI Project)
TIWG	Testing & Interoperability Working Group
TLA	Three Letter Acronym
TLA	Top-Level Aggregation (RFC2450)
TLC	Test Loop Combination
TLD	Third Level Domain
TLDN	Temporary Local Directory Number
TLP	Test Level Point
TLV	Type Length Value
TM	TeleManagement (Forum)
TM	Transmission and Multiplexing (ETSI TC)
TMC	Time-slot Management Channel
TMCC	TM Chairman's Coordination committee
TMF	TeleManagement Forum
TMGB	Telecommunications Main Grounding Busbar
tML	telecommunications Markup Language
TML	Test Model
TMM	Telecom-based Multimedia
TMN	Telecommunication Management Network
TMN1	Temporal Reference Model for the Near Term 1
TMN8	Video Codec Test Model, Near-Term, Version
TMSI	Temporary Mobile Station Identity
TNR	Transmit Not Ready
TNS	Transit Network Selection
TNV	Telephone Network Voltage (IEC 950)
TO	Technical Organization
TO	Telecommunications Outlet
TOA	Time of Arrival
ToC	Table of Contents
TOC	Terminated Open Circuit
TOLR	Transmit Objective Loudness Rating
TOM	Telecom Operations Map (TeleManagement Forum)
TON	Type of Number
ToR	Terms of Reference
TOR-G	Technical Organization Reform Group
ToS	Type of Service (RFC1349)
TOS	Type Of Service octet in IPv4
TOSCA	Text and Office Systems Content Architecture
TOSQA	Telecommunication Objective Speech Quality Assessment, algorithm of T-Nova Berkom
TP	Test Protocol
TP	Test Purposes
TPDU	Transport Protocol Data Unit (X.224)
TPS	Transport Protocol Specific
TPS-TC	Transport Protocol Specific-Transmission Convergence
TPKT	Transport Packet (T.123)
TPUI	Temporary Portable User Identity
T/R	Tip/Ring
TR	Technical Report
TR	Technical Requirements (TIA committee)
TR	Telecommunications Room
TR	Temporal Reference
TR	Text Relay (QH/16)
TR	Transmit Ready
TR2TF	Technical (TR- Committee) Regulatory Reform Task Force
TRAC	Technical Recommendations Application Committee (ETSI)
TRC	TIPHON Resolution Capability
TREG	Telecommunications Regulatory Email Grapevine
TRIC	TIA Regulatory Issues Committee
TRIO	TIPHON Remote InterOp
TRIP	Telephony Routing Information Protocol
TRL	Transmit Loudness Rating
TRMMDS	Technical Requirements MultiMedia Distribution Systems
TRP	Temporal Reference for Prediction
TRQ	Technical Requirements document (T1)
TRRTF	Technical (TR- Committee) Regulatory Task Force
TRWNT	Technical Requirements Wireline Terminals
TRWST	Technical Requirements Wireless Terminals
TS	Technical Specification
TS	Time Slot (Q6/15)
TS	Transport Stream
TS PCR	Transport Stream Program Clock Reference
TSA	Transmitting Subscriber internet Address
TSACC	Telecommunication Standards Advisory Council of Canada
TSAG	Telecommunication Standardization Advisory Group (ITU)
TSAP	Transport layer Service Access Point
TSAPI	Telephony Server API
TSB	Telecommunications Standardization Board (ITU)
TSB	Telecommunications Systems Bulletin (TIA)
TSC	Technical Standards Committee
TSEG	Test Signals Experts Group (ITU-T Q6/15, Q4/12, Q6/12)
TSG	Technical Specification Group
TSI	Terminal Support Interface
TSI	Transmitting Subscriber Identification
TSP	Telephony Service Provider
TSS	ITU-Telecommunications Standardization Sector (CCITT)
TSS	Test Suite Specification
TSSC	Technical Standards Subcommittee (TIA)
TSSS	Temporal, SNR, and Spatial Scalability
TSV	Transport Area (IETF)
TSWG	Transport Sub Working Group (DSL Forum)
TT	ANSI Translation Type
TTC	Telecommunication Technology Committee (Japan)
TTC	TIA Technical Committee
TTCM	Turbo Trellis Coded Modulation
TTCN	Tree and Tabular Combined Notation
TTE	Telecommunications Terminal Equipment
TTF	Technical Task Force
TTIB	Transparent tone in band
TTL	Time To Live
TTP	Trusted Third Party
TTT	Trans-European Network Telecom (TIPHON)
TTY	Teletype
TU-C	Transceiver Unit - Central Office End
TUP	Telephony User Part
TV	Television
TWA	Time Weighted Average
TWAIN	Scanner Interface API: Technology Without An Interesting Name (MFPI work)
TWDM	Thin Wavelength Division Multiplexing
TWIM	Terrestrial Wireless Interactive Multimedia
TWP	Technical Working Procedures (ETSI)
TX	Transmit
-U-
U/S	Upstream
UA	User Agent
UAP	Unified Accelerated Procedure
UART	Universal Asynchronous Receiver Transmitter
UAS	Unavailable Seconds (Rec. G.997.1)
UAWG	Universal ADSL Working Group
UB	Unlicensed Band
UBC	Uniform Building Code
UBC	University of British Columbia
UBIC	Unbilled Itemized Calls
UBR	Unspecified Bit Rate
UBS	User-Based Solution
UC-PAM	Ungerboeck Coded PAM
UCAN	User Circuit mode Access to Network (T1S1)
UCF	Unregistration Confirm
UCI	Universal Communications Identifier
UCS	Universal Character Set
UCS	Universal multiple octet coded Character Set
UDDI	Universal Description, Discovery and Integration (industry initiative)
UDI	Unrestricted Digital Information
UDLC	Universal Digital Loop Carrier
UDP	User Datagram Protocol (IETF)
UEP	Unequal Error Protection
UDP	User Datagram Protocol
UDPTL	Facsimile UDP Transport Layer protocol
UGST	User's Group on Software Tools
UHF	Ultra High Frequency
UI	Unit Interval
UI	User Interface
UI	Unnumbered Information (V.42)
UIH	Unnumbered Information with Header check
UIM	User Identity Module
UL	Underwriters Laboratories
ULL	Unbundled Local Loop
ULM	Unified Management Framework
ULP	Uneven Level Protection
Um	Radio (Air) Interface between Mobile and Base Station
UME	UNI Management Entity
UML	Unified Modeling Language
UMTS	Universal Mobile Telecommunications System
UMV	Unrestricted Motion Vector (H.263)
U-N	User-Network
UNA	User Network Aspects
UNAA	Universal Network Access Arrangement
UN/ECE	United Nations Economic Commission for Europe
UNERM	Unacknowledged Non-Error Recovery Mode
UNH	University of New Hampshire
UNI	User-Network Interface
UP	User Part
UPBO	Upstream Power Back-Off
UPC	Usage Parameter Control
U-PCS, UPCS	Unlicensed PCS
UPED	User Premises Equipment Division
uPnP	Universal Plug and Play Forum
UPQoS	User Perceived QoS
UPR	Users Performance Requirements
UPS	Uninterrupted Power Supply
UPT	Universal Personal Telecommunications (ITU)
UPTSP	Universal Personal Telecommunications Service Providers
UPU	Universal Postal Union
UQ	Utility Quality
URI	Unified Resource Identifier
URI	User Premises Equipment Regulatory Issues
URL	Uniform Resource Locator
URN	User Requirements Notation Focus Group
URQ	Unregistration Request
US	Under Study
US1	TDMA Wireless Speech Coder
USAG	United States Advisory Group
USB	Universal Serial Bus
USCEL	United States Council of EMC Laboratories
USH	University of Sherbrooke
USIM	Universal Subscriber Identity Module (3GPP Working Group T3)
USM	User Security Model
uSMS	universal Short Message Service
USNC	United States National Committee
USOC	Uniform Service Order Codes
USTA	United States Telecom Association
USTR	US Trade Representative
UT	Upper Tester (TIPHON)
UTAM	Unlicensed Transition and Management
UTC	Universal Time Code
UTF	UCS (Universal Character Set) Transformation Format
UTL	Utility
UTP	Unshielded Twisted Pair
UTRAN	UMTS Radio Access Network
UU, U-U	User to User
UUI	User-User Interface
UUIE	User-to-User Information Element
UUT	Unit Under Test
UVG	Universal Voice Grade
UVLC	Universal Variable Length Codeword
UWCC	Universal Wireless Communications Consortium
UXP	Unequal Erasure Protection
-V-
V&M	Voice and Multimedia WG (ATM Forum)
V&V	Validate and Verify
VA	Viterbi Algorithm
VAD	Voice Activity Detector
VADSL	Very high speed ADSL
VAF	Voice Activity Factor
VAME	Voice on ATM Multiplication Equipment
VAR	Value Added Resellers
VBD	Voice Band Data
VBI	Vertical Blanking Interval
VBRnrt	Variable Bit Rate non-real time
VBRrt	Variable Bit Rate real time
VBSMC	Variable Block-Size Motion Compensation
VBST	Variable Block Size Transform
VBV	Video Buffer Verification
VC-RDI	Virtual Circuit-Remote Detect Indicator
VC	Video Control
VC	Virtual Channel
VC	Virtual Circuit (Rec. I.610)
VC	Virtual Connection
VC	Virtual Container
VC	Volume Control
VCC	Virtual Channel Connection
VCEG	Video Coding Experts Group
VCELS	Vertical Cavity Surface Emitting Laser
VCOM	vcom.drv for Microsoft Chicago
VCI	Virtual Channel Identifier
VCL	Video Coding Layer
VCR	Video Cassette Recorder
VCS	Voice Controlled Services
VCV	Video Complexity Verifier
VDC	Volts DC
VDI	Verification and Demonstration Implementation
VDI	Verification, Design and Implementation
VDMA	German Telefax Association, Verband Deutscher Maschinen und Anlagenbau
VDSL	Very high speed DSL
VDTI	Voiceband Data Transmission Interface
VED	Voice Enhancement Devices
VEMMI	Versatile MultiMedia Interface (ETSI)
VEMMI	Videotex Enhanced Man Machine Interface Service
VERA	Video Error Resilience Algorithm
VESA	Video Electronic Standard Association
VHE	Virtual Home Environment
VHF	Very High Frequency
VHN	Versatile Home Network
VHN	VESA's Home Networking
V-I	Voltage - Current
VIA	Vendors ISDN Association
VICS	Vehicle Information and Communications System Service (Japan)
VIM	Vendor Independent Messaging
VIMP	Virtual Interoperability Meeting Place
VISIONng	Voice over IP Service IntroductiON - new generation
VLAN	Virtual Local Area Network
VLBR	Very Low Bit Rate
VLBVT	Very Low Bit rate Video Telephony
VLC	Variable Length Coding
VLCD	Variable Length Coding and Decoding
VLD	Variable Length Decoding
VLDB	Very Large Database
VLF	Visitor Location Function
VLR	Visitor Location Register
VLRIN	Visitor Location Register Identification Number
VLSI	Very Large Scale Integration
VM	Verification Model
VMAC	Voice Mobile Attenuation Code
VMLA	Virtual Mobile Location Area
VMM	Virtual Meeting Management
VMOA	Voice and Multimedia over ATM (ATM Forum WG)
VMS	IBM operating system
VMS	Voice Mail System
VMWI	VoiceMail Waiting Indication
VoADSL	Voice over ADSL
VoATM	Voice over ATM
VoB	Voice over Broadband
VOC	VDSL Operations Channel
VOD	Video on Demand
VoDSL	Voice over DSL
VoI	Voice over Internet
VoIP	Voice Over Internet Protocol
VoMBN	Voice over Multi-Service Broadband Networks
VoMPLS	Voice over MPLS
VoMSDN	Voice over Multi-Service Data Networks
VON	Voice on Network Coalition
VON	Voice On the Net
V-ONT	Video-Optical Network Terminal
VOP	Video Object Planes
VOP	Voice over Packet (Network)
VoSTM	Voice over Synchronous Transfer Mode
VOX	Voice Operated Transmission
VP	Virtual Packet
VP	Virtual Path (ATM Forum, Q2/15)
VPF	Virtual Private Facility
VPI	Virtual Path Identifier
VPIM	Voice Profile for Internet Mail
VPM	Voice Privacy Mask
VPMASK	Voice Privacy Mask
VPN	Virtual Private Network
VQ	Vector Quantization
VQE	Voice Quality Enhancement (ITU-T)
VQEG	Video Quality Experts Group
VQM	Video Quality Metric
VQmon	ETSI TS101 329-5 Annex E, Method for Determining an Equipment Impairment Factor using Passive Monitoring
VR	Vertical Resolution
VSAT	Very Small Aperture Terminal satellite services
VSB	Vestigial Side Band
VSC	Vertical Service Codes
VSELP	Vector Sum Excited Linear Predictive Coding
VSOG	Vertical Service Ordering Guidelines
VTOA	Voice and Telephony Over ATM
VTQME	Voice Transmission Quality Mouth to Ear (ETSI)
VTR	Video Tape Recorder
VTS	Voice Tone Support
VTU	VDSL Transceiver Unit
VTU-C	VDSL Transceiver Unit - Central
VTU-O	VDSL Transeiver Unit at the Optical network unit
VTU-R	VDSL Transceiver Unit - Remote Terminal
V-UNI	Virtual UNI
VWC	Vector Wavelet Coding
-W-
W3C	World Wide Web Consortium
WAC	WuÕs AC engine (proposed) (JVT)
WACS	Wireless Access Communication Systems
WAN	Wide Area Network
WAP	Wireless Application Protocol
WARC	World Administrative Radio Conference
WB	Wide Band
WBS	Wireless Business System
WCAT	Wireless Cellular Action Team
WCDMA	Wideband Code Division Multiple Access
WCPE	Wireless CPE
WCS	Wireless Communications System
WD	Wireless communications Devices
WD	Working Document
WDM	Wavelength Division Multiplexing
WDS	Wireless Data Service
WEB-CAM	Web Camera
WEPL	Weighted Echo Path Loss
WER	Word Error Rate
WFOM	Wait for Overhead Message
WFQ	Weighted Fair Queuing
WG	Working Group
WI	Waveform Interpolation
WI	Work Item
WIDE	Widely Integrated Distributed Environment
WIMS	Wireless Multimedia and Messaging Services
WIN	Wireless Intelligent Network
WINS	BT's Wideband Impulsive Noise Survey
WIS	Wide area Interface Sublayer
WLAN	Wireless LAN
WLL	Wireless Access Local Loop
WLNP	Wireless Local Number Portability
WML	Wireless Markup Language (used in WAP)
WMOPS	Weighted MOPS
WOSA	Windows Open Services Architecture
WOT	World Ordering Team (TeleManagement Forum)
WP	Working Party (ITU)
WPA	Working Party A
W-PBX	Wireless PBX
WPM	Work Program (ETSI)
WPT	Wireless Personal Terminal
WRC	World Radiocommunication Conference
WRE	Wireless Residential Extension
WSC	World Standardization Conference
WT	Working Text (DSL Forum)
WTLR	Wireless Terminal Location Registration
WTPF	World Telecommunication Policy Forum (ITU)
WTSA	World Telecommuncations Standardization Assembly (ITU)
WTSC	World Telecommunication Standardization Conference (ITU)
WUPE	Wireless User Premises Equipment (TR-41.6)
WWW	World Wide Web (Internet)
-X-
XAPI	eXtensive Application Programming Interface
XAPIA	X.400 API Association
xDSL	All the different DSL technologies
XER	XML Encoding Rules
xGCP	Gateway Control Protocol including MGCP, SGCP and IPDC
XID	eXchange IDentification
XIWT	Cross-Industry Working Team
XML	eXtended Markup Language
XNI	Customer Network Interface
xoIP	FoIP, MoIP, VoIP
XOR	eXclusive OR
XRS	Message not understood
xRU	all the different Regenerator/Repeater Units
XSD	XML Schema Definition
XTI	X-open Transport Interface
xTAAB	Advisory Board on Other Access Technologies
xTU-C	All the different Transceiver Units - Central
xTU-R	All the different Transceiver Units - Remote
-Y & Z-
YCbCr	Color space used in digital video
YCC	Color space used in digital video
ZHP	Z = input impedance of the ADSL transceiver; HP = high pass (ETSI RTS_TM-06006)
ZLP	Zero Loss Plan

More Acronym Definitions: