This is a List of telephony terminology and acronyms which relate to telephony networks.

A

Advanced Intelligent Network The Intelligent Network (IN) is the standard network architecture specified in the ITU-T Q.1200 series recommendations. It is intended for fixed as well as Global System for Mobile Communications, mobile telecommunication, telecom networks. It al ...

, (AIN), see also IN or Intelligent Network * Automatic number announcement circuit (ANAC) *

Automated Attendant In telephony, an automated attendant (also auto attendant, auto-attendant, autoattendant, automatic phone menus, AA, or virtual receptionist) allows callers to be automatically transferred to an extension without the intervention of an operator/ ...

*ACD -

Automatic call distributor An automated call distribution system, commonly known as automatic call distributor (ACD), is a telephony device that answers and distributes incoming calls to a specific group of terminals or agents within an organization. ACDs direct calls based ...

* Articulation score

B

Blue box A blue box is an electronic device that produces tones used to generate the in-band signaling tones formerly used within the North American long-distance telephone network to send line status and called number information over voice circuits. ...

- a device that was used to bypass the normal long-distance call switching tones typically used to obtain free calls.

C

* Call originator - (or ''calling party'', ''caller'' or ''A-party'') a person or device that initiates a telephone call by dialling a telephone number. *

Call waiting Call waiting is a telephone service where a subscriber can accept a second incoming telephone call by placing an in-progress call on hold—and may also switch between calls. With some providers it can be combined with additional features such a ...

- a system that notifies a caller of another incoming telephone call by sounding a sound in the earpiece. *

Called party The called party (in some contexts called the "B-Number") is a person who (or device that) answers a telephone call. The person who (or device that) initiates a telephone call is the calling party. In some situations, the called party may number m ...

- (or ''callee'' or ''B-party'') * Caller *

Calling party The calling party (in some contexts called the "A-Number") is a person who (or device that) initiates a telephone call. The person who, or device that, receives a telephone call is the called party (or callee or B-party). In some countries, it ...

Conference call A conference call is a telephone call in which someone talks to several people at the same time. The conference call may be designed to allow the called party to participate during the call or set up so that the called party merely listens into ...

(multi-party call) * COCOT

D

Dial peer A dial peer, also termed addressable call endpoint, initiates or obtains calls within a telephone network. See also *VoIP *Session Initiation Protocol The Session Initiation Protocol (SIP) is a signaling protocol used for initiating, maintainin ...

* Dial tone *

Distribution frame Distribution may refer to: Mathematics *Distribution (mathematics), generalized functions used to formulate solutions of partial differential equations *Probability distribution, the probability of a particular value or value range of a varia ...

* Dual-tone multi-frequency signaling (DTMF)

E

Emergency telephone number Most public switched telephone networks have a single emergency telephone number (sometimes known as the universal emergency telephone number or the emergency services number) that allows a caller to contact local emergency services for assis ...

* End instrument *

Engset calculation In queueing theory, the Engset formula is used to determine the blocking probability of an M/M/c/c/N queue (in Kendall's notation). The formula is named after its developer, T. O. Engset. Example application Consider a fleet of c vehicles and N ...

Erlang unit The erlang (symbol E) is a dimensionless unit that is used in telephony as a measure of offered load or carried load on service-providing elements such as telephone circuits or telephone switching equipment. A single cord circuit has the capac ...

F

Fax Fax (short for facsimile), sometimes called telecopying or telefax (the latter short for telefacsimile), is the telephonic transmission of scanned printed material (both text and images), normally to a telephone number connected to a printer o ...

- (contraction of ''facsimile'') a device connected to the telephone network to enable documents to be scanned and sent to a receiving fax machine *Frame - A

distribution frame Distribution may refer to: Mathematics *Distribution (mathematics), generalized functions used to formulate solutions of partial differential equations *Probability distribution, the probability of a particular value or value range of a varia ...

, a set of open wiring racks where circuits are cross connected to trunks and equipment

H

Handoff In cellular telecommunications, handover, or handoff, is the process of transferring an ongoing call or data session from one channel connected to the core network to another channel. In satellite communications it is the process of transf ...

* Handover *

Help desk A help desk is a department or person that provides assistance and information usually for electronic or computer problems. In the mid-1990s, research by Iain Middleton of Robert Gordon University studied the value of an organization's help desks ...

Howler tone The off-hook tone (also off-hook warning, howling tone, or howler tone) is a telephony signal for alerting a user that the telephone has been left off-hook without use for an extended period, effectively disabling the telephone line. North Ameri ...

(see ROH tone) * Hunt Group

I

Infrastructure Infrastructure is the set of facilities and systems that serve a country, city, or other area, and encompasses the services and facilities necessary for its economy, households and firms to function. Infrastructure is composed of public and priv ...

Intelligent Network The Intelligent Network (IN) is the standard network architecture specified in the ITU-T Q.1200 series recommendations. It is intended for fixed as well as mobile telecom networks. It allows operators to differentiate themselves by providing v ...

(IN) * Interface functionality * Inside plant * Intelligent Network Interface Device (iNID) - replaces the

Network Interface Device upTwo simple NIDs, carrying six lines each, on the outside of a building upA German copper phone line termination box called '' Abschlusspunkt LinienTechnik'' (APL, " Demarcation point") In telecommunications, a network interface device (NID; ...

outside a subscriber's house like when customers subscribe to AT&T's

U-verse U-verse TV is a DirecTV brand of IPTV service. Launched on June 26, 2006, U-verse included broadband Internet (now AT&T Internet or AT&T Fiber), IP telephone (now AT&T Phone), and IPTV (U-verse TV) services in 48 states.Interactive voice response Interactive voice response (IVR) is a technology that allows telephone users to interact with a computer-operated telephone system through the use of voice and DTMF tones input with a keypad. In telecommunications, IVR allows customers to interac ...

(IVR) *

ISDN User Part The ISDN (Integrated Services Digital Network) User Part or ISUP is part of Signaling System No. 7 (SS7), which is used to set up telephone calls in the public switched telephone network (PSTN). It is specified by the ITU-T as part of the Q.76x se ...

(ISUP)

L

Line Line most often refers to: * Line (geometry), object with zero thickness and curvature that stretches to infinity * Telephone line, a single-user circuit on a telephone communication system Line, lines, The Line, or LINE may also refer to: Art ...

Local loop In telephony, the local loop (also referred to as the local tail, subscriber line, or in the aggregate as the last mile) is the physical link or circuit that connects from the demarcation point of the customer premises to the edge of the commo ...

* Long-distance operator

O

On-premises wiring On-premises wiring (customer premises wiring) is customer-owned telecommunication transmission or distribution lines. The transmission lines may be metallic (copper) or optical fiber, and may be installed within or between buildings. Premises ...

* Operator assistance *

Outside plant In telecommunication, the term outside plant has the following meanings: *In civilian telecommunications, outside plant refers to all of the physical cabling and supporting infrastructure (such as conduit, cabinets, tower or poles), and any asso ...

P

* Patch-through access *

Permanent signal Permanent signal (PS) in American telephony terminology, or permanent loop in British usage, is a condition in which a POTS line is off-hook without connection for an extended period of time.Telcordia Technologies, GR-505-CORE Issue 2, December ...

* Person-to-person *

Plain old telephone service Plain old telephone service (POTS), or plain ordinary telephone system, is a retronym for voice-grade telephone service employing analog signal transmission over copper loops. POTS was the standard service offering from telephone companies from 1 ...

, or "POTS" *

Public Switched Telephone Network The public switched telephone network (PSTN) provides infrastructure and services for public telecommunication. The PSTN is the aggregate of the world's circuit-switched telephone networks that are operated by national, regional, or local telep ...

(PSTN) * Pupinization

R

* Receiver Off-Hook tone (ROH) *

Red telephone box The red telephone box, a telephone kiosk for a public telephone designed by Sir Giles Gilbert Scott, is a familiar sight on the streets of the United Kingdom, Malta, Bermuda and Gibraltar. Despite a reduction in their numbers in recent years, ...

* Red box *

Regional Bell Operating Company The Regional Bell Operating Companies (RBOC) are the result of '' United States v. AT&T'', the U.S. Department of Justice antitrust suit against the former American Telephone & Telegraph Company (later known as AT&T Corp.). On January 8, 1 ...

(RBOC) * Ringer equivalency number (REN) * Ringing signal * Rural radio service

S

Smartphone A smartphone is a portable computer device that combines mobile telephone and computing functions into one unit. They are distinguished from feature phones by their stronger hardware capabilities and extensive mobile operating systems, whi ...

Station-to-station Operator assistance refers to a telephone call in which the calling party requires an operator to provide some form of assistance in completing the call. This may include telephone calls made from pay phones, calls placed station-to-station, per ...

Signalling System 7 Signalling System No. 7 (SS7) is a set of telephony signaling protocols developed in 1975, which is used to set up and tear down telephone calls in most parts of the world-wide public switched telephone network (PSTN). The protocol also perform ...

(SS7)

T

* Tandem signaling * Tandem switch * Transaction Capabilities Application Part (TCAP) *

Telemarketing Telemarketing (sometimes known as inside sales, or telesales in the UK and Ireland) is a method of direct marketing in which a salesperson solicits prospective customers to buy products or services, either over the phone or through a subsequen ...

Telephone A telephone is a telecommunications device that permits two or more users to conduct a conversation when they are too far apart to be easily heard directly. A telephone converts sound, typically and most efficiently the human voice, into e ...

Telephone booth A telephone booth, telephone kiosk, telephone call box, telephone box or public call box is a tiny structure furnished with a payphone and designed for a telephone user's convenience; usually the user steps into the booth and closes the booth ...

Telephone call A telephone call is a connection over a telephone network between the called party and the calling party. First telephone call The first telephone call was made on March 10, 1876, by Alexander Graham Bell. Bell demonstrated his ability to "ta ...

Telephone card A telephone card, calling card or phonecard for short, is a credit card-size plastic or paper card, used to pay for telephone services (often international or long-distance calling). It is not necessary to have the physical card except with a st ...

Telephone directory A telephone directory, commonly called a telephone book, telephone address book, phonebook, or the white and yellow pages, is a listing of telephone subscribers in a geographical area or subscribers to services provided by the organization that ...

Telephone exchange telephone exchange, telephone switch, or central office is a telecommunications system used in the public switched telephone network (PSTN) or in large enterprises. It interconnects telephone subscriber lines or virtual circuits of digital syste ...

Telephone tapping Telephone tapping (also wire tapping or wiretapping in American English) is the monitoring of telephone and Internet-based conversations by a third party, often by covert means. The wire tap received its name because, historically, the monitorin ...

Teletraffic engineering Teletraffic engineering, telecommunications traffic engineering, or just traffic engineering when in context, is the application of transportation traffic engineering theory to telecommunications. Teletraffic engineers use their knowledge of stat ...

* Time Division Multiplexing (TDM) * Trap and trace * TWX

V

Vertical service code A vertical service code (VSC) is a sequence of digits and the signals star (*) and number sign (#) dialed on a telephone keypad or rotary dial to enable or disable certain telephone service features. Some vertical service codes require dialing of ...

Voicemail A voicemail system (also known as voice message or voice bank) is a computer-based system that allows users and subscribers to exchange personal voice messages; to select and deliver voice information; and to process transactions relating to ind ...

Voice over Internet Protocol Voice over Internet Protocol (VoIP), also called IP telephony, is a method and group of technologies for the delivery of voice communications and multimedia sessions over Internet Protocol (IP) networks, such as the Internet. The terms Internet t ...

(VoIP)

W

Western Union The Western Union Company is an American multinational financial services company, headquartered in Denver, Colorado. Founded in 1851 as the New York and Mississippi Valley Printing Telegraph Company in Rochester, New York, the company cha ...

Wide Area Telephone Service Wide Area Telephone Service (WATS) was a flat-rate long-distance service offering for customer dial-type telecommunications in some of the countries that adhere to the North American Numbering Plan. The service was between a given customer phone ...

(WATS) *

WATS line Wide Area Telephone Service (WATS) was a flat-rate long-distance service offering for customer dial-type telecommunications in some of the countries that adhere to the North American Numbering Plan. The service was between a given customer phone ...

Wireless network A wireless network is a computer network that uses wireless data connections between network nodes. Wireless networking is a method by which homes, telecommunications networks and business installations avoid the costly process of introducing ...

* Wireless Telephony Applications Interface (WTAI) *

Wi-Fi Wi-Fi () is a family of wireless network protocols, based on the IEEE 802.11 family of standards, which are commonly used for local area networking of devices and Internet access, allowing nearby digital devices to exchange data by radio waves ...

Z

* Zenith number

Acronyms

{{Telecommunications Technical terminology Telephony