My objective was to convert this Cisco enterprise IP phone into a standalone SIP phone for use with my VoIP service provider. By installing a Linksys SPA9000 VoIP PBX box as an local intermediate (to bypass the NAT protocol), I have achieved basic placing and receiving calls. As expected with this model, voice quality at both ends is excellent.
The key is to create the correct SEP-mac-.cnf.xml file to direct the firmware load and the configuration settings. This phone arrived with a recent version of Cisco's SCCP firmware. From the Cisco downloads area, I selected the most recent version of the SIP firmware to replace that.
When the phone arrived (showing, by the way, no visible signs of wear), because I already had a good starting point for the configuration file, TFTP server, ring list, dial plan, and so on, the phone powered up and registered essentially the first time I plugged it in. (Note these phones require a PoE switch or injector since they derive their power from the Ethernet connection.)
(Updated May 8, 2021) My VoIP provider suggested switching UDP to TCP and turning on the phone's NAT configuration setting (which entails telling it your public IP address). With other change to the NAT settings at the VoIP provider's end, the phone now registers directly with the provider and places and receives calls. I'd really like to get the Directory button to bring up a local phone directory, but that is still a work-in-progress.
With the success in registering directly with my VoIP provider, I went ahead and purchased a second 7965G from the same seller. The second phone isn't quite as pristine as the first, but still marginally passes Amazon's visual inspection criteria.
(Updated May 10, 2021) The Directory button now brings up my personal contacts list. It turns out that Cisco IP phones don't work with the Apache web server.
Jason Salter
CFortC
KKhirfan
Sara kaur