We have the same issue.
We used for call status detection at!swicallprog=2 at command.
This command is not implemented to MC7304.
Is there something another at command for extended call status?
We need detect alerting (ring back) into outgoing call.
For example MC8795V/MDC8775V
swicallprog 1,0,2,0,0 - dialing
swicallprog 1,0,3,0,0 - alerting (ring back)
swicallprog 1,0,0,0,0 - connect