Hi,

MT8880 does not have ring detector on it, rhather it has call progress.

Perhaps you mean that it can detect while the other called phone is ringing, yes it detect the status that ring is going to the other party.

How you sent the music on it, interested to know, please.

sending serial data over DTMF is a bit slow.

You can try standard FSK chips. Try a search on the web.

There are stnadard stand alone chips available which take RS232 as in send FSK over phone and convert back it to RS232 at the other end.

Hope it helps.

Babar