Heheee... You can actually google for DTMF and find out what it is, like
http://en.wikipedia.org/wiki/DTMFWhen you call Zain Customer Care on 111 (from a Zain number) or when you call Access Kenya on 3600000 or Wananchi Group on 3292000 you will encounter Automated Attendant (
http://en.wikipedia.org/wiki/Automated_attendant) systems or IVR (
http://en.wikipedia.org/wiki/IVR) which rely on DTMF to help you navigate the menu presented on the system.
I am working on something like that using a GSM gateway, an IP PBX and a special software.
The Automated Attendant is build around the software, running on a PC.
I know very little around this area, but have been doing RTFM all the time while implementing the same. Nothing to brag about in a skunkworks exhibition:-)