Core Issue
If there is a requirement that the public switched telephone network (PSTN) caller should only hear silence and not hear any Tone on Hold (ToH) or Music on Hold (MoH), then MoH can be turned off but the caller still hears the ToH. ToH is what the external PSTN callers hear when they are placed on hold by an IP phone in Cisco CallManager 4.x.
Resolution
In order to disable ToH when the caller is placed on hold by an IP phone, complete these steps:
- Create a new wav file and call it silence.wav.
- Place the silence.wav file in the DropMOHAudioSourceFilensHere directory.
- Go to the CalManager Admin, choose Service > MOH and insert a new audio stream number. Then select silence.wav as the audio source.
- Go to the Device Pool for your phones and gateway and set the Audio Source file to silence.wav.
- Update and reset the device pool (reset all devices in the pool).
For more information related to these steps, refer to Music On Hold.