Dual-tone multi-frequency
Overview
Signalling (telecommunications)
In telecommunication, signaling has the following meanings:*the use of signals for controlling communications...
over analog telephone lines in the voice-frequency band between telephone
Telephone
The telephone , colloquially referred to as a phone, is a telecommunications device that transmits and receives sounds, usually the human voice. Telephones are a point-to-point communication system whose most basic function is to allow two people separated by large distances to talk to each other...
handsets and other communications devices and the switching center. The version of DTMF that is used in push-button telephone
Push-button telephone
The push-button telephone was first invented in 1941, and is a telephone with push-buttons or keys, and which eventually replaced rotary dial telephones that were first used in 1891. The first push-button telephone was invented in the labs of Bell Telephone; however, these models were only...
s for tone dialing is known as Touch-Tone. It was developed by Western Electric
Western Electric
Western Electric Company was an American electrical engineering company, the manufacturing arm of AT&T from 1881 to 1995. It was the scene of a number of technological innovations and also some seminal developments in industrial management...
and first used by the Bell System
Bell System
The Bell System was the American Bell Telephone Company and then, subsequently, AT&T led system which provided telephone services to much of the United States and Canada from 1877 to 1984, at various times as a monopoly. In 1984, the company was broken up into separate companies, by a U.S...
in commerce, using that name as a registered trademark.
