Common Terminology in the Communication Industry

Updated: Feb 25

Below you will find a Glossary of terms in the communication industry that you may need to refer to every-so-often.

Advanced Telecom Computing Architecture (ATCA) -- AdvancedTCA

A series of specifications regarding the design elements required for next-generation carrier-grade communications equipment to determine high-speed interconnect technologies, next-generation processors, reliability, manageability and serviceability.


An information form that is represented by a continuous and smoothly varying amplitude or frequency changes over a certain range such as voice or music.

Analog Telephone Adapter (ATA)

Converts analog signals from a conventional phone into a format for transmission over an internet connection, and vice versa at the receiving end.

Asymmetric Digital Subscriber Line (ADSL)

Most homes and small business users are connected to an asymmetric DSL (ADSL) line. Refer to DSL definition below for more info on DSL. ADSL divides up the available frequencies in a line on the assumption that most Internet users look at, or download, much more information than they send, or upload. Under this assumption, if the connection speed from the Internet to the user is three to four times faster than the connection from the user back to the Internet, then the user will see the most benefit (most of the time).

Asynchronous Transfer Mode (ATM)

The international standard for cell relay in which multiple service types (voice, video, data) are conveyed in fixed-length (53-byte) cells.

Back Haul

Back Haul is a process of extending the use of communication facilities or more efficient circuits by using communicating routing lines that are longer than would be typical for a specific type of service. Back haul allows for cost effective sharing of facilities by either sharing network facilities (such as a switching system) or communication circuits (sharing long haul lines with many more users).

Circuit Switching

A process of connecting two points in a communications network where the path (switching points) through the network remains fixed during the operation of a communications circuit. While a circuit switched connection is in operation, the capacity of the circuit remains constant regardless of the amount of content (e.g. voice or data signals) that is transferred during the circuit connection.

CODEC (Coder/Decoder)

A device that can encode or decode a signal.

Competitive Local Exchange Carrier (CLEC)

A company that builds and operates communication networks in metropolitan areas and provides its customers with an alternative to the local telephone company.

Customer Premises Equipment (CPE)

The telephone equipment residing on a customer site.


Stands for direct inward dialing (also known as direct dialing inward), a service that allows you to have numerous individual phone numbers for each person or workstation internally that run off of a small block of dedicated telephone numbers. With DID you can have multiple lines connected to a PBX all at once without requiring each line to be physical connected to the PBX. For example, if an organization has 25 employees and each employee has a separate telephone number, or extension, within its physical location, the organization can rent 10 physical trunk lines from the telephone company that will allow 10 phone calls to take place simultaneously. Others would have to wait for an available line and anyone dialing into the system while all 10 lines are in use would get either a busy signal or be channeled into a voice mail system. A DID system does not require a PBX operator and can be used for fax and voice transmissions.

IP Telephony (Internet Protocol Telephony)

Technology using the Internet Protocol's packet-switched connections to exchange voice, fax, and other forms of information that have traditionally been carried over dedicated circuit-switched connections of the public switched telephone network (PSTN). Also known as IP Phone Service, VoIP Phone Service, and Broadband Phone Service.

ITIL (IT Infrastructure Library)

A widely accepted approach to IT service management which provides a cohesive set of best practice supported by a comprehensive qualifications scheme, accredited training organizations, and implementation and assessment tools.


A delay impacting the quality of a voice conversation.


Multiplexing is a process used by a communications system to coordinate and allow more than one user to access the communications channels within the system. There are four basic access multiplexing technologies used in wireless systems: frequency division multiple access (FDMA), time division multiple access (TDMA), code division multiple access (CDMA) and space division multiple access (SDMA).

Network Operations Center

The physical space where telecommunications is managed, monitored and supervised.

OSI Reference Model

A reference model to standardize communication systems. The model standardized nomenclature across existing protocols and provided guidelines for new protocols using 7 layers.


A unit of data that is routed between an origin and a destination on the Internet or any other packet-switched network.

Packet Switching

Sending and receiving data over alternate, multiple network channels. Packets can be sent in order yet be received in a different order - only to be put back in the correct order in fractions of a second.

PBX (Private Branch Exchange)

A private telephone network used within an organization with users sharing a certain number of outside lines for making telephone calls external to the PBX.

Public Switched Telephone Network (PSTN) - Plain Old Telephone Service (POTS)

The world's collection of interconnected voice-oriented public telephone networks, both commercial and government-owned.

Quality of Service (QoS)

The measuring of transmission rates, error rates, and other characteristics for improved call quality.

Session Border Controller

An interface to a network firewall that facilities the secure hand-off of voice packets from one IP network to another. In an enterprise network the SBC controls the communications session as it crosses the border of the LAN.

Session Initiation Protocol (SIP)

A signaling format for Internet Telephony involving multimedia elements such as video, voice, chat, gaming, and virtual reality.

Softphone (Software Telephone)

A software program on your PC (desktop or laptop) enabling you to make and receive calls over the Internet (VoIP) using a headset, or a microphone and speakers, in place of a telephone.

Transmission Control Protocol (TCP)

A session layer protocol that coordinates the transmission, reception, and retransmission of packets in a data network to ensure reliable (confirmed) communication. The TCP protocol coordinates the division of data information into packets, adds sequence and flow control information to the packets, and coordinates the confirmation and retransmission of packets that are lost during a communication session. TCP utilizes Internet Protocol (IP) as the network layer protocol.

Uninterruptible Power Supply Systems (UPS)

A battery power supply used to maintain power in the event of a power outage.

User Datagram Protocol (UDP)

UDP is a high-level communication protocol that coordinates the one-way transmission of data in a packet data network. The UDP protocol coordinates the division of fition into packets and adds sequence information to the packets that are transmitted during a communication session using Internet Protocol (IP) addressing. This allows the receiving end to receive and re-sequence the packets to recreate the original data file or block of data that was transmitted. UDP adds a small amount of overhead (control data) to each packet relative to other high-level protocols such as TCP. However, UDP does not provide any guarantees to data delivery through the network.

Voice over IP (VoIP)

The delivery of voice information using the Internet Protocol (IP).