Hi,
I am electronic engineer and I have done may projects related to phone lines.
I am expert with DTMF, call waiting, caller ID etc..
But from your description I understand that you want only a simple mp3 player to play file when answering the phone.
And line detection
And ring detection
Am I correct ?
I will design for you a nice product if you will let me.
Nice, pretty and w o r k i n g .
Waiting for your respond
Regards,
Amir