Touch-Tone

For optimal use, push-button telephones using dual tone multifrequency (DTMF), more commonly known as Touch-Tone capability, rather than the older and slower pulse dial system. Touch-Tone technology was first made available in 1963 with the introduction of the first button phone, but the pulse was still supported by many telephone conversations. The keyboard format is rapidly becoming the standard numbering system in the United States, particularly in the enterprise market, and eventually became the standard in the world. button Touch-Tone format is also used for all cell phones.

Phone keys are usually organized in a grid 3-for-4, including the numbers from zero to nine, plus the star key (*) and pound sign / hash (#) to accommodate various additional services and controlled by the calling client characteristics. specific frequencies are assigned to each column and row of buttons in the keypad of the telephone, the columns of the wafer push-button have tones and rows in the block have tones. When a button is pressed, a two-tone signal is generated on the basis of the frequencies for the selected row and column. A signal representative of the tone is then transmitted over the telephone line to the telephone.