I had a similar issue with Jabber client v.11.7(1), I fixed the deskphone issue by downloading the Jabber Desk Phone Services Interface from Cisco Downloads.

Thank you for posting the solution. This fixed my issue :)

Thanks for the clarification. I missed understood the issue. 

I had a similar issue. The problem was on the Automatic Available, it was set to "Disabled". It needs to be Enabled. In CCX go to Subsystems-> RmCm-> Resources (find Agent). Under Automatic Available click Enabled.