Why is the volume of softphone calls lowered in the Windows volume mixer?

What can I do if the volume of softphone calls is automatically lowered in the Windows volume mixer?

Solution:

(This solution is available from XPhone Server version 8.0.512, for remedy in earlier version please contact support).

Remedy is a parameter which can be set centrally on the server side. By configuring the parameter, the registry key is ignored.

Set this as follows in the admin interface under Telephony > Gateways > SIP > SIP Gateway > "Parameter sets for lines" > edit used parameter set (default here is "Standard").

Parameters: SoftphoneClientConfig

Value: PUBLIC/EnableAudioDucking||false

Note: If multiple parameter sets are in use, you have to find the parameter set used for the lines concerned and add the parameter here.