Modify single Polycom configuration setting without affecting existing settings

I have a Polycom 650 that is currently up and running. The user has created contacts, set line key preferences, etc. After the phone had been in use for a week, the user noticed that the handset volume returns to the default after every call, which is highly annoying. With a little research, I’ve learned that I need to change the voice.volume.persist.handset setting in sip.cfg.

I’ve been manually configuring phones up to this point. (I know that’s bad practice, but my justification was: multiple locations, difficulty getting tftp in place, and a history of Linksys phones that are simple to configure via the web interface. With a couple Polycoms in the mix, I’m starting to think a proper provisioning system is in order.)

My question is, is there a way for me to change just a single setting on an otherwise configured phone? If I have to re-enter things like server settings, that’s fine, but I’d really like to avoid wiping out the user’s personalizations like local contacts, speed dials and line key settings. Thanks in advance for any advice.


I guess I have a related question; is there a way to copy the existing sip.cfg from a Polycom phone?


The phone does not contain any files. It reads parameters from the files as it boots. The files would be on your tftp, http or ftp server you use to provision the phone.

I believe that’s true in an environment where you’re using a provisioning server. This phone was configured manually via its web interface with no tftp server to get configs from and has been running that way ever since. It’s been rebooted as well, and the configs stick. I’ve since set up a test network with a machine running the freepbx distro that’s also the tftp server. I’m basically hoping for a way to connect the phone to the test network and push a config to it that changes that one option. Going forward I plan to provision phones centrally, but for this one-off instance, I’m just trying to find a way to change the one option without losing the user’s personalizations and preferences.