History

In the 1950, AT & T conducted extensive studies and concluded that the push-button dialing was much faster than rotary dialing. On 18 November 1963, the first electronic push-button system with touch-tone dialing was provided by Bell Phones AT & T customers.

The push-button telephone was introduced to the public in the cities of Carnegie and Greensburg, Pennsylvania, with touch-tone available for a surcharge. The first push-button telephone, the 1500 West had only ten buttons. A model of twelve button with the asterisk / star (*) and pound / hash (#) key was released shortly after, replacing the old model.

Although pushbutton keypad phones made their debut to the public in 1963, the old rotary phone was still common for many years. In the 1970, the majority of phone users still had a rotary phone. Adoption of the push-button phone is stable, but it took a long time for them to appear in some areas. At the beginning, it was mostly companies that have adopted push-button phones. In 1979, the touch-tone phone has been gaining in popularity, but it was not until the 1980 that the majority of clients in push-button telephones in their homes, in the 1990, c 'was the vast majority.

Some exchanges more support pulse and rotary phones are generally considered obsolete. rotary phones are now widely regarded as a novelty, and are not compatible with some features modern telephone, although enthusiasts may adapt pulse phones using a converter pulse tone.