Radio units provide the following audible/visual indications :
- Go-ahead tone.
- Call set-up in progress.
- Called party engaged in another call.
- Called party engaged in another call, call queue is too large to join, call terminated.
- Called party not obtainable.
- Network busy.
- Interface to other network/s not available.
- Call in progress has been pre empted.
- Incoming emergency call.
