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A telephone keypad is a keypad installed on a push-button telephone or similar telecommunication device for dialing a telephone number. It was standardized when the dual-tone multi-frequency signaling (DTMF) system was developed in the Bell System in the United States in the 1960s – this replaced rotary dialing , that had been developed for ...
Telephone numbers listed in 1920 in New York City having three-letter exchange prefixes. In the United States, the most-populous cities, such as New York City, Philadelphia, Boston, and Chicago, initially implemented dial service with telephone numbers consisting of three letters and four digits (3L-4N) according to a system developed by W. G. Blauvelt of AT&T in 1917. [1]
image/svg+xml. File history. Click on a date/time to view the file as it appeared at that time. Date/Time ... Description=ISO 9995-8 telephone keypad diagram. ...
Date/Time Thumbnail Dimensions User Comment; current: 21:30, 2 May 2007: 571 × 463 (36 KB): Sakurambo~commonswiki {{Information |Description=Telephone keypad with letter mapping corresponding to the ITU E.161 standard |Source=Created using Adobe Illustrator CS2 |Date=2 May 2007 |Author= Philip Ronan}}
A push-button telephone is a telephone that has buttons or keys for dialing a telephone number, in contrast to a rotary dial used in earlier telephones.. Western Electric experimented as early as 1941 with methods of using mechanically activated reeds to produce two tones for each of the ten digits and by the late 1940s such technology was field-tested in a No. 5 Crossbar switching system in ...
The Australian letter-to-number mapping was A=1, B=2, F=3, J=4, L=5, M=6, U=7, W=8, X=9, Y=0, so the phone number BX 3701 was in fact 29 3701. When Australia around 1960 changed to all-numeric telephone dials, a mnemonic to help people associate letters with numbers was the sentence, "All Big Fish Jump Like Mad Under Water eXcept Yabbies ."
The main advantages of phonewords over standard phone numbers include increased memorability and increased response rates to advertising. They are easier to remember than numeric phone numbers; thus, when businesses use them as a direct response tool in their advertising (radio, television, print, outdoor, etc.), their memorability tends to have a favorable effect on response rates.
DTMF keypad layout Combination of 1209 Hz and 697 Hz sine waves, representing DTMF "1" The DTMF telephone keypad is laid out as a matrix of push buttons in which each row represents the low frequency component and each column represents the high frequency component of the DTMF signal. The commonly used keypad has four rows and three columns ...