should abort when hitting timeout

when the phone has bad reception placing calls fails like

Okt 01 18:21:32 pureos calls[851]: Error starting outgoing call ModemManager call to `+49xxxxxxxxx': Zeitüberschreitung wurde erreicht
Okt 01 18:21:49 pureos ModemManager[510]: <info>  [modem1/call0] user request to hangup call
Okt 01 18:21:51 pureos ModemManager[510]: <info>  [modem1/call0] user request to hangup call
Okt 01 18:22:14 pureos calls[851]: Error hanging up ModemManager call to `+49xxxxxxxx': Zeitüberschreitung wurde erreicht
Okt 01 18:22:16 pureos calls[851]: Error hanging up ModemManager call to `+49xxxxxxxx': Zeitüberschreitung wurde erreicht
Okt 01 18:22:37 pureos ModemManager[510]: <warn>  [modem1/call0] couldn't start call: Serial command timed out
Okt 01 18:22:37 pureos ModemManager[510]: <info>  [modem1/call0] call state changed: dialing -> terminated (unknown)
Okt 01 18:22:37 pureos ModemManager[510]: <warn>  [modem1] port ttyUSB1 timed out 2 consecutive times
Okt 01 18:22:42 pureos ModemManager[510]: <warn>  [modem1] couldn't load call list: Serial command timed out
Okt 01 18:22:42 pureos ModemManager[510]: <warn>  [modem1] port ttyUSB1 timed out 3 consecutive times
Okt 01 18:22:44 pureos ModemManager[510]: <warn>  [modem1] port ttyUSB1 timed out 4 consecutive times
Okt 01 18:22:46 pureos ModemManager[510]: <warn>  [modem1] port ttyUSB1 timed out 5 consecutive times

(Zeitüberschreitung wurde erreicht = ETIMEDOUT)

There's no 'beep' sound, the speaker stays perfectly silent. Hitting the red button does nothing until much later. It would likely be better to cancel the call right away when hitting the first timeout so the user gets feedback about the problem (that's what my other phone does under these circumstances).