You can use Windows Jabber to control your desk phone.
In Jabber software, you will need to make sure that your phone is selected under the "Device for calls" option.
- Press on the
or 
icon at the bottom of the Jabber. 
- Select your phone model from the drop-down list. The device should be Cisco 79XX, 78XX, or 81XX depending on the model phone you have.
- Once you change this setting, your Jabber will no longer be a softphone and will control your desk phone.