I've been experiencing issues with my UC320W and I've been working with my VoIP provider Callcentric to resolve the issues. The problem occurs when a phone call is placed on hold, or the phone call is transferred to another phone in the office. When the call is resumed, there is no audio on our line and sounds like the call was dropped, but the remote caller always calls back and says they could hear us talking. So it appears that only one way audio is being transmitted from our end.
I asked Callcentric to look into two specific cases where this occurred, and their reply was the following:
"We have reviewed our logs for both of the calls that you've pointed out -- which we have uploaded onto this ticket (please see the attached pcaps labelled "Jul 17 2014 16-40-30(gmt) - 15127446000.pcap" and "Jul 17 2014 18-30-38(gmt) - 15126594180.pcap"); and from our logs; the only issue we do see that will cause the symptom you've described is that your Cisco UC320 seems to be performing a Re-Invite on those 2 calls. Please note that when transferring calls between local extensions within your PBX, or transferring calls towards another number, your PBX should not be sending anything to our servers except for a 200OK SIP packet as mentioned on the following FAQ (http://www.callcentric.com/faq/4/197
). If possible does your Cisco UC320 have any options pertaining to Re-INVITEs (from the screen captures that you have provided, we do not see any options). And if it does, can you disable it as it shouldn't be Re-Inviting the call back to us."
The two .pcap files they are referring to are attached in a zip file.
If anyone could offer insight into what would be necessary to resolve this issue I would greatly appreciate it.