How to turn off the Voicemail [ VM ] tone detection. (broken dial tone)
Your voicemail service provider sends special signals to the unit to let you know that you have new voicemail messages.
If you hear a series of dial tones followed by a continuous dial
tone after you press the call 
button, you have new voicemail
messages. The unit can detect these signals automatically.
Turn this feature off in the following situations:
- You do not subscribe to voicemail service.
- Your phone is connected to a PBX.
- The indicator is on and there are no messages.
- Press [ MENU # 3 3 2 ].
- Press the arrow up ▲ or down ▼ button to select the desired setting.
- Press [ SAVE ].
This feature is not available on all models.
Operation may vary by model. Refer to your models Operating Manual for specific procedure.