"...the probelm is how can i detect that the called phone has gone OFF HOOK means that the call has been received. MT8880 has a feature CALL PROGRESS.... which gives the tones being received on the phone line including the calling tone in the shape of wave form..."

I know, I sound like a broken record skipping and playing the same track over and over this past year, but the way I have done this in the past is to monitor the call progress cadence. Once your ("your" being your device's) state machine has progressed to the RINGBACK state, subsequent cadence changes may transition to, for example, a special information tone, voice detected, etc. Cadence (RINGBACK) timeout might indicate that the called end picked up the phone.

What are you calling?