Acronyms and their Definitions

The telecommunications community has a language all of its own

Acronyms and Definitions


[tel-i-kuh-myoo-ni-key-shuh nz]

1: communication at a distance (as by telephone), the transmission of information, as words, sounds, or images, usually over a great distance, in the form of electromagnetic signals, as by telegraph, telephone, radio, television, or mobile device.

2: technology that deals with telecommunication —usually used in plural


Program Memory – (also known as text, code) is used for permanent saving program being executed.
Data Memory – data memory that is common across multiple channels. Tables, .cinit. const, etc.)
Scratch Data – data memory that does not need to be preserved from one algorithm call to the next. Scratch data can be shared with other algorithms or other instances of the same algorithm in a non-preemptive environment.
Per Channel Data – data memory that needs to be preserved from one algorithm call to the next.. Also known as instance data or persistent data.
Stack is an area ofmemory allotted for automatic variables. Stack  is used for static memory allocation
Heap – Persistent – dynamically allocated memory that must be maintained from one algorithm call to the next. This would typically be allocated at initialization time. (Rarely used by Adaptive Digital algorithms)

Stack is used for static memory allocation and Heap for dynamic memory allocation, both stored in the computer’s RAM.

Heap – Scratch – dynamically allocated memory that is allocated on the fly and freed before the return from any algorithm functions.  (Rarely used by Adaptive Digital algorithms)



ADPCM Adaptive Digital Pulse Code Modulation – A compression technique which records only the difference between samples and adjusts the coding scale dynamically to accommodate large and small differences. ADPCM is simple to implement, but introduces much noise.

ADSL Asymmetrical Digital Subscriber Line

AGC Automatic Gain Control

AMR Adaptive Multi-Rate

ASCII American Standard Code for Information Interchange

ANSI American National Standards Institute

Analog A form of transmission that is a continuous wave electrical signal that varies in frequency and/or amplitude in response to the variations of a physical phenomena such as human speech or music. In telephony, your voice is captured by a diaphragm within the telephone which causes a magnet to vibrate creating a continuously fluctuating electrical signal that is passed through a wire circuit and received on the other end.

APC Adaptive Predictive Coding

API Application Program Interface – The interface (calling conventions) by which an application program accesses operating system and other services. An API is defined at source code level and provides a level of abstraction between the application and the kernel (or other privileged utilities) to ensure the portability of the code.


Bandwidth A relative range of frequencies that can carry a signal on a transmission medium.

BIOS Basic Input / Output System

Bps Bits per second

Broadband A broad bandwidth communications channel capable of supporting high capacity ISDN services or other integrated voice, data and video applications.

Buffer A temporary storage location for data information being sent or received. Usually located between two different devices that have different abilities or speeds for handling the data. The buffer acts like a reservoir, capturing the data and then letting it out at speeds the lower river can handle without, hopefully, flooding or overflowing the banks.


Call Processing The method by which telephone calls are identified and routed through the network. Usually refers to the processing of a call within a telephone switch.

CELP Code Excited Linear Predictive (Prediction)

Channel The path along which a communications signal is transmitted.

CLECs Competitieve Local Exchange Carriers

CNG Comfort Noise Generator

CO Central Office – The local switching facility of a telephone company to which telephones are connected.

CPU Central Processing Unit


Digital A form of transmission that transforms analog signals such as speech into a series of electrical or optical pulses that represent the binary digits 0 and 1. The first step of a digital transmission is sampling the analog waveform and converting it into a stream of numerical data. This data is then converted into a form such as electronic pulses for a wired network, optical light waves for transmission over fiber optics or into radio waves for wireless transmissions.

DSL Digital Subscriber Line or Digital Subscriber Loop – A family of digital telecommunications protocols designed to allow high speed data communication over the existing copper telephone lines between end-users and telephone companies.

DSP Digital Signal Processor (specialized computer chip) – A specialized digital microprocessor used to efficiently and rapidly perform calculations on digitized signals that were originally analog in form (e.g. voice). The big advantage of DSP lies in the programmability of the processor, allowing parameters to be easily changed.

DTMF Dual Tone Multi Frequency – “Touch-tone.” A method used by the telephone system to communicate the keys pressed when dialing. Pressing a key on the phone’s keypad generates two simultaneous tones, one for the row and one for the column. These are decoded by the exchange to determine which key was pressed.


ERL Echo Return Loss

ERLE Echo Return Loss Enhancement

Ethernet A local area data network used for connecting computers, printers, workstations, terminals, etc., within the same building. Ethernet operates over twisted wire and over coaxial cable at speeds up to 100 Mbps.

ETSI European Telecommunications Standards Institute


Frequency The rate at which an electrical current alternates, usually measured in Hertz. Frequency equals the number of complete cycles of current occurring in one second.

Full duplex Simultaneous transmission and reception of information.


GSM Global System for Mobile – A digital European cellular standard, based on TDMA technology, specifically developed to provide system compatibility across country boundaries. This compatible network enables GSM cellular users to use a single cellular phone throughout Europe, most of Asia, and parts of North and South America and have every call billed to one account. Countries have been rapidly building GSM networks, resulting in over 160 million fully working subscribers in over 125 countries.

GUIGraphical User Interface


Half duplex Alternating the transmission and reception of information between users. Sometimes also referred to as “Ping-Pong” operation. This is the basic mode of operation of most TDD and TDMA systems, where transmission and reception are separated in time.

HDSL High Speed Digital Subscriber Loop

Hertz Then unit of measuring frequency (one cycle per second).

HSCWDHigh Speed Circuit Switched Data


IAD Integrated Access Device

IEEE Institute of Electrical and Electronics Engineers

ISSP Interim Interswitch Signaling Protocol

IP telephony Internet Protocols telephony

ITU International Telecommunication Union


KHz KiloHertz (thousands of Hertz)


LAN Local Area Network

LEC Line Echo Canceller, or Local Exchange Carrier

Local loop A communications link (usually wire), between a telephone subscriber’s location and the local telephone Central Office.


MHz MegaHertz (millions of Hertz)

MCU Multiplexer Control Unit

MIMO Multiple-input multiple-output

MIPS Millions of Instructions Per Second – This is a measure of the per-channel processor utilization.

MOS Mean Opinion Score – This is a formally tested subjective measure of speech quality. The scale goes as high as 5.0, which is the rating for uncompressed speech (8 K samples/sec with 16 buts per sample).


OEMs Original Equipment Manufacturers

OptimipsT Adaptive Digital’s method for reducing CPU utilization.

OS Operation system


PABX Private Automatic Branch Exchange

PBX Private Branch Exchange

PCM Pulse Code Modulation

PCU Packet Control Unit

POTS Plain Old Telephone Service/System

PPSN Public Packet Switched Network

PSTN Public Switched Telephone Network


QCELP Qualcomm Codeword Excited Linear Prediction

QoS Quality of Service


RAM Random Access Memory – The primary memory in a computer. Memory that can be overwritten with new information.

RAS Remote Access Service/Server

Rate The channel bandwidth in kilobits per second required to pass the compressed speech data.


SCELP Spike Code Excited Linear Prediction

SCSI Small Computer System Interface, pronounced “scuzzy”

SCN Switched Circuit Network

SDK Software Development Kit

SDR Signal-to-Distortion Ratio

SDSL Symmetrical high bit rate Digital Subscriber Line

Simplex (Sx) Operating a channel in one direction only with no ability to operate in the other direction. For example, one side of a telephone conversation is all that could be carried by a simplex line.

SIP Session Initiation Protocol (IETF)

SMP Simple Multiplexing Protocol

SNR Signal-to-Noise Ratio

SP Service Provider

Speech encoding Utilizing signal processing techniques to convert an analog voice waveform into a digital bit-stream. Then digital bit-stream can then be transmitted over communications or data networks.

SRL Signal/Structural Return Loss

STM Synchronous Transfer Mode

SOC System on a Chip

SOHO Small Office Home Office

SW Software

Sx Simplex


TCM Time Compression Multiplex

TCP Transmission Control Protocol

TDM Time Division Multiplexing – A means of creating multiple circuits on a single transmission channel by rapidly connecting terminals one at a time in a recurring time ordered sequence.

TDMA Time Division Multiple Access – A method of digital wireless transmission that allows a large number of users to share access (in a time ordered sequence) to a single radio frequency channel without interference by assigning unique time slots to each user within the channel.

Third Generation (3G) Usually used in reference to the next generation digital mobile network.

TI Texas Instruments

TIA Telecommunications Industry Association

TSP Telephony Service Provider

TTP Trusted Third Party


UI User Interface

USTA United States Telecom Association


VAD Voice Activity Detector

VBD Voice Band Data

VBV Video Buffer Verification

VHF Very High Frequency

VLBR Very Low Bit Rate

VoDSL Voice over Digital Subscriber Line

VoIP Voice over Internet Protocols

VON Voice On the Net

VOX Voice Transmit

VQE Voice Quality Enhancement

VSELP Vector Sum Excited Linear Predictive Coding


WAN Wide Area Network

Wireless Radio-based systems that allow transmission of information without a physical connection, opposed to transmission systems, that require a physical connection, such as copper wire or optical fiber.


XDAIS eXpress DSP Algorithm Interoperability Standard

XDAIS-DM eXpress DSP Algorithm Interoperability (Digital Media) Standard

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