Missing Audio/ video option in Skype for Business client?
Basically audio / video and enterprise voice (Dial-pad) feature control via administrator. You must request Audio/Video and enterprise voice (dial-pad) feature enable to your account.
So how does the Skype for Business (Lync) client know what features to make available when the user signs in?
The answer is through information received by the client via in-band provisioning from server. The Skype for Business (Lync) client sends out a SIP SUBSCRIBE requesting provisioning information: Below can be see in Skype for Business (Lync) client UCCAPILOG.
SUBSCRIBE sip:email@example.com SIP/2.0
The response is a SIP/2.0 200 OK and contained in the response is the setting we're interested in:
The telephonyMode setting can contain a couple of different values, depending on what the user is configured for:
1. None = PC-to-PC only
2. NoAudioVideo = Audio/Video Disabled
3. RCC = Remote Call Control
4. UC = Enterprise Voice
5. RCC Only = Remote Call Control only
Below screenshot taken from SfB/Lync Server Control Panel: