NethVoice: Snom D8XX phones no longer support HTTP commands

[andrea-marchionni]

Description

Snom D8XX phones no longer support HTTP commands for remote control. NethVoice CTI click-to-call still works by falling back to manual click-to-call, while NethLink fails with a phone communication error.

Evaluate whether Snom provides an alternative remote-control method for this phone series, and/or add the same manual click-to-call fallback to NethLink.

Steps to reproduce

1. Configure a Snom D8XX phone for CTI and NethLink.
2. Start a click-to-call operation from CTI.
3. Verify that CTI falls back to manual click-to-call and the call starts.
4. Start the same operation through NethLink.

Expected behavior

NethLink starts the call using a supported Snom method or falls back to manual click-to-call.

Actual behavior

NethLink fails and reports a communication error with the phone.