Polycom makes a robust line of highly adaptable SIP phones that are used on many platforms. The download page for the Soundpoint IP product family is here. It is planned to add whether the unit is POE capable, number of lines, and other common features to these phones as time permits.
THIS PAGE is considered stale. You should use this page as a current source of Polycom information:
http://wiki.sipfoundry.org/display/sipXecs/Polycom+Phones
http://downloads.polycom.com/voice/voip/sip_sw_releases_matrix.html
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