Does flitan = waqar.... maybe ,the post times are quite similar..
only craig/steve (with IP log access) would know for sure.

could be just a cut and paste job

but is this the first post where waqar has contributed ,rather than taken?.


PBX ro some kind of rely based system ...
To interface a telephone with microcontroller you need to firstly know following things:-
1) Telephone Set require minimumm of 12 Volts , 24 Volts to operate and controller require 5 Volts so first thing is to supre impose these.
2)so firstly u need to have a SLIC circuit or SLIC IC to separate 5 volts and 24 Volts.
3) Next thing for DTMF the best is MT3271 coz it can be connected with microcontroller serially so less pins are used.
4) further thing i can guide u if u can explain your project..
and rem this is the forum on the net which can provide maximum help there is no source on the earth i mean on internet from where u can get help on telephony interface with controller