Turn off phone keypad sounds

To silence keypad sounds it has been suggested here that the ringtone volume be turned down entirely or the phone put on silent mode. These are not not solutions. These are workarounds. Another person said, on what authority I don't know, that the tones are generated by the carrier so there is no way to silence them. Maybe they are a function of the carrier. That's not relevant. Wherever the tones come from, there is in fact some way to silence them without silencing the ringer. Listen as an android user dials their phone while not on silent mode: no keypad sounds. Does anyone know any way to make an iphone do this basic function?