Why should DTMF be set to long on a cell phone What is DTMF short used for?

Dual-tone multifrequency

A method used by the telephone system to recognise the keys pressed when dialling. Pressing a key on the phone's keypad generates two simultaneous tones, which are decoded by the exchange to determine which key was pressed.

Dual-tone multifrequency

A method used by the telephone system to recognise the keys pressed when dialling. Pressing a key on the phone's keypad generates two simultaneous tones, which are decoded by the exchange to determine which key was pressed.