how to monitor phone call progress?

[gabriel]

hello:
I'm using my modem to call some numbers, by opening the corresponding serial port then sending the ATDT<number> command, it works fine.
But now I want to know if there is already a dial tone or not, and if after dialing the line is busy, ringing, not answering etc.....in plain C language preferably (just to avoid TAPI using).
How that? I know there is a status register that I should read, but I didn't found adequate documentation about that.

any help is appreciated.

thanks in advance

[falcon _bd]

AT+MORING
SHOW STATE OF MOBILE ORIGINATED CALL