How frequency is converted to numeric number,for example i clicked on '1' of my keypad and it is shown in screen of my mobile or computer? I seem, this happens not only for number but also for others keys of keyboard.What is the fact behind it?

Question

anonymous · Answer

Programs and circuits.

anonymous · Answer

You might be referring to Dual-tone Multifrequency signalling used in telephony... hope this helps... :) http://www.engineersgarage.com/tutorials/dtmf-dual-tone-multiple-frequency

anonymous · Answer

thanks for your help @Orion and @Johnbc 
is DTMF is used in modern technology like android,iphone and others  ?

anonymous · Answer

yes it is... apps in android, iphone and others depending on your skills in programming can do it....