![]() ![]() The Labs’ work proceeded through the fifties, with miniature oscillators replacing the reeds as technology evolved, and eventually transistors replacing the oscillators. Each key plucked two reeds, sending a signaling tone down the line. In a 1948 trial, a group of subscribers in Media, PA, tested a push-button telephone, with two rows of five keys. Dialing a seven-digit number could easily require ten seconds, especially as higher digits took longer to turn and then return on the dial than lower digits.īell Labs’ search for alternatives to the dial originated in the 1940s. Q and Z were omitted, giving three letters above each remaining digit. And as telephone numbers consisted of both exchange names and numbers, such as Pennsylvania 6-5000, (dialed as PE 6-5000), the dials soon sported letters above all digits except 1 and 0. Over the next four decades, all but a handful of exchanges converted to dial service. To educate the subscribers on the new system, Bell showed short subjects explaining the system at local movie theaters. If you go back far enough, to the early twentieth century, all telephones were manual-to make a call, a subscriber lifted the telephone receiver off from a switch hook, and waited for an operator to ask “number please.” While there were earlier automatic systems elsewhere, in 1919 the Bell System began, one local telephone exchange at a time, to replace the manual switchboards and telephones with electromechanical automatic exchanges, controlled by pulses generated by subscribers operating telephones with rotary dials. national telephone monopoly, and its famed R&D unit, Bell Telephone Laboratories. And why are those keys arranged in that particular order? The answers to these questions go back many decades to the wired landline telephone system to AT&T’s Bell System, the old U.S. But what does “dial the number” mean -there is no dial, just a pattern of virtual keys on a screen. The number hasn’t been saved in the phone’s address book, so he or she brings up the virtual key pad and dials the number. ![]() Someone picks up a smartphone to make a call. 12-button Touch-Tone telephone, 1968 (Courtesy AT&T Archives and History Center) ![]()
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