A colleague had this nasty problem that he managed to solve – he found lots (hundreds) of people on the Internet had the same problem but there were no solutions out there – so I convinced him to share how he solved the nasty problem:
Polycom IP SoundStation IP 5000 - calls last exactly 20 seconds and then they are disconnected.
The logs on the SwitchVox PABX showed the following error when tracing the SIP messages passing between PBX and Polycom IP 5000. This is the error code that I suspected was causing the issue:
(Critical Response) -- See doc/sip-retransmit.txt
It took a while, but changing the protocol that IP5000 uses to connect to the PABX from TCP/IP to UDP seems to have fixed the problem - now the calls work properly :)
It now also connects to the SwitchVox PABX immediately compared to previously when using TCP/IP it took at least 10 seconds.
So now, once the phone is plugged in and boots up, it immediately connects and calls longer than 10 seconds are now no problem!
For others trying to figure out how to log onto the phone’s web page to change the settings:
use username (upper case ‘P’): Polycom
(This is the default username and password)