The rotary dial is a device mounted on or in a telephone or switchboard that is designed to send electrical pulses, known as pulse dialing, corresponding to the number dialed. The early form of the rotary dial used lugs on a finger plate instead of holes. Almon Brown Strowger filed the first patent for a rotary dial, U.S. patent #486,909, on December 21, 1891, that was later issued to him on November 29, 1892.
The modern version of the rotary dial with holes was first introduced in 1904 but did not enter service in the Bell System until 1919. The rotary dial was gradually supplanted by Dual-tone multi-frequency pushbutton dialing, introduced at the 1962 World's Fair, which uses a keypad instead of a dial. Some telephone systems in the US no longer recognize rotary dialing by default, but will only support push-button phones.
Read more about Rotary Dial: History, General Form, Function
Famous quotes containing the word dial:
“A man is reputed to have thought and eloquence; he cannot, for all that, say a word to his cousin or his uncle. They accuse his silence with as much reason as they would blame the insignificance of a dial in the shade. In the sun it will mark the hour. Among those who enjoy his thought, he will regain his tongue.”
—Ralph Waldo Emerson (1803–1882)