Registering Default App for Soft Phone

Hello,

Under Facetime and various third party apps such as Jabra Connect, you can choose a preferred Soft Phone that is (somehow) registered with macOS.

I've been searching high and low and I can't seem to find any information on how to register a new Soft Phone for users to choose from these lists.

Any advice appreciated :)

Bill
Registering Default App for Soft Phone
 
 
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