Who invented touch tone telephone

For example, a customer can enter credit card or identification numbers by pressing buttons on a keypad, or he or she can choose from among various options by listening to a menu and pressing the button that corresponds with the desired option. To take full advantage of these new capabilities, major telephone service providers around the world began to order the manufacture of touch tone phones that would accurately emit the right type of tones to activate those features.

Deployed to the business community initially, the technology quickly spread to the private sector. By , the touch tone phone was the telephone of choice for most users in many parts of the world. With the deregulation of the telephone industry in the United States in , the touch tone telephone became even more important. When the dial is returning to its resting position, the telephone breaks the current between the telephone and the switching office.

The switching office counts the number of times that current flow is interrupted, which indicates the number that had been dialed. The dial-pulsing technique was particularly appropriate for use in the first electromechanical telephone switching offices, because the dial pulses actually moved mechanical switches in the switching office to set up the telephone connection. The introduction of touch-tone dialing into electromechanical systems was made possible by a special device that converted the touch-tones into rotary dial pulses that controlled the switches.

Initially, plucked tuned reeds were proposed. The dial pulses of the telephone were no longer needed to control the mechanical switching process at the switching office. When electronic control was introduced into switching offices, telephone numbers could be assigned by computer rather than set up mechanically.

This meant that a single touch-tone receiver at the switching office could be shared by a large number of telephone customers. Before , telephone switching offices relied upon rotary dial pulses to move electromechanical switching elements.

Touch-tone dialing was difficult to use in systems that were not computer controlled, such as the electromechanical step-by-step method. The material on this site may not be reproduced, distributed, transmitted, cached or otherwise used, except with the prior written permission of Advance Local.

Community Rules apply to all content you upload or otherwise submit to this site. Ad Choices. Fact-forward news for readers like you who want to know more. Subscribe today. The keypad was the runaway winner; the calculator arrangement didn't even make the top five. The story goes that Bell Laboratories contacted the biggest calculator manufacturers to share their research findings, but only received bemused shrugs in response; none of them had ever done any user testing.

There's an apocryphal story that the keypad was upturned to stop skilled calculator operators entering phone numbers too quickly. Klein's arrangement is now used on ATMs, door locks, vending machines and medical equipment — a prime example of data-driven design. Join thought-provoking conversations, follow other Independent readers and see their replies.