On http://www.microsoft.com/uc/partners_hardware.mspx you will find a number of devices, which have been optimized for Office Communicator 2007. Being optimized for Office Communicator 2007 means that the device implements a number of features, including wide band audio, presence state icon and Human Interface Devices (HID) commands like mute, speaker phone, off-hook etc.
However, even if the device you are using implements these features, they might not work for you when using Office Communicator 2007. The reason is most likely that you are not enabled for Enterprise Voice in OCS 2007.
As a user you can easily check, if you are enabled for Enterprise Voice. If you are enabled for Enterprise Voice your Office Communicator 2007 UI will show the Call Forwarding button as highlighted with yellow in this screen shot