Polycom 331 and PoE
Tanner Electronics in Dallas has a box of unregulated 24V DC, 600 mA power supplies for $3.95. I have a Polycom IP 330 I picked up off of Craig's list and I need a power supply. What I have not figured out is whether the Polycom power supply is regulated or not. I am thinking that the phone does not need a regulated supply. Can anyone tell me if the power supply from Polycom is regulated?
I needed a 331 power supply to test out a phone I got from one of my customers - they were using PoE and didn't have any of the bricks around. I got a 24V-1A PS from Radio Shack and plugged that in - the phone works fine with one exception.
The phone will connect and upgrade/downgrade/load config from the t*f*t*p server without a hitch, but as soon as the "Running sip.ld" goes by, the phone reboots.
After the firmware is installed, the phone will boot up without a hitch and sit until I plug it into the network. As soon as the pins make contact the ethernet port goes active, the phone reboots.
So, my guess is that something in the sip.ld is sensing the active network connection and causes the phone to reboot. It does it silently, though, which leads me in the direction of a power issue (if it was a soft failure, the error would still log on the way out), so it's reasonable to assume that this unregulated 24v supply might be the problem. I have a Polycom power brick on the way (should be here today or Monday) and I'll be able to narrow down the problem even more after that.
I've tested the configuration further, and on a PoE connection (regular Cisco 48v, like you'd get from a Cisco switch or injector) the phone boots and connects to the network without a problem.
Conclusion: Unregulated 24V power supplies are not sufficient for the Polycom 331 phone. The PoE connection will work with a 48V supply like Cisco, et al.
So, my conclusion is that you can use any 24V supply to boot the phones off-line (to reformat the file system, for example) but that they are not sufficient for use in a live network.
Phone System 