0
1
2
3
4
5
6
Time axis in seconds
Audio Signals
Ring tone
Internal busy tone
Internal dialling tone
External dialling tone/
continuous tone
Positive acknowledgement tone
Negative acknowledgement tone
Special internal dialling tone
Special external dialling tone
Call-waiting tone
Special sensor tone
Calls
External call
Internal call
VIP call
Callback
Sensor call
The tones and ringer signals mentioned above are valid for Germany; in other countries they may differ.