Woh , how come Lance Austin is getting such great replies...i think Michael Karas took about 1/2 hour to write this code...any ways its all about the likes and dislikes people have for Pakstani People.....may be Lance is from USA etc... that's why every one is helping me upto the max. extend...
i think iam speaking too much..iam sorry for that but its true...

Ok can i use the above mentioned method for my 8 lines Intercom..to detect Off-HOOKS and then perform the dialing , dial tone and other task and at the same time keep on checking other bits....?

please do explain something for me too about off-hook and on hook conditions..

P1 is used to detect off hook / on hook signals..

The Numbering of Telephone Sets is as :-
only pulse dailing..

21, 22, 23, 24 , 25, 26, 27 ,28

When ever the Set goes off hook controller provide it Dial Tone for 10 Seconds via MT8816 and then wait for pulse dialing...

now if another telephone goes off hook or the previous goes on hook then the method is applicable or not..