Hi Narin,

I don't find the CP mode much useful as during the call progress monitoring even a slight line noise will give a false result.

Say, if you have dialed a number and ring is going then you can get a tone burst at the IRQ pin coherent with the ring tone from exchange. But if during silence between two rings you get a noise then still you will get an out put at the IRQ pins which will disturb your timers functions in the code and get a wrong impression that perhaps the line is busy as the silence duration is not equal to the standard.

May by carfully desiging the software we can handle this problem


Simon.