This question has come up a couple times. How can I disable Inbound Ring on MOC but still keep all of my other windows sounds. The sound options for communicator are hidden, but there are a lot of options once you find them.
Open Communicator 2007 R2 Options and go to the Alerts Section. From here you will select the “Configure Sounds” button.
In the Sounds you will find a Category of Microsoft Office Communicator 2007 R2. Under this section look for a option of “Incoming Call”.
Set the Sounds to “None” and apply changes.
That’s it, now Communicator will not play ring tone on incoming calls.