Shahzad Aslam wrote:
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2- How can i detect various other tones likes Busy signal, Noraml telephone tone or B Party telephone ringing tone.

I have designed devices using embedded modems chips for many countries (U.S.A., Canada, Australia, U.K., Holland, Switzerland, Sweden, and Singapore, to name a few), all of which have passed that country's homologation. The most reliable and flexible way I have found to perform call progress detection (even with cheap hardware i.e., no off-the-shelf call progress chip), I have just now contributed to 8052.com here. It is based on energy detect transition counts and total energy time during a specified window of time. I'm not at liberty to provide the actual source code, but this outline should get you started.