Share your experience!
Settings -> sounds --> system --> Dialpad touch tones
I have enabled and disabled and checked, but doesn't find any difference.
what is the main purpose of this option and where can i check its functionality.
it makes the sound each time you dial a phone number when your gona call some 1, it wont make any sounds anywhere else than that area 
Just checked it now, odd it didnt make any sound like you said 😕 so i will keep looking and see what it's used for 
Hmmm i guess the sound volume is too low to hear when you dial on touch pad, try putting up the headset. XD
increase the volume of the "Ringtone & notifications" and you should hear it.
Tried as you said, but it doesn't make any difference. Earlier i was getting sound while using dial pad. 2 days back i have noticed that dial pad not making any sounds.
Is it because of new firmware update .253 ?
to make it sound anything when you dial a number go to -----> settings -----> volume and make sure both top and 1 under is set to max, after that you should hear a dial sound when you dail a number 
the third one is only for alarm clock and notify.
Now i can hear the Dialpad touch tones by Increasing the volume of Music, Video, games and other media to the max level.
