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Community Member

UC320W cannot hear caller after hold or transfer

Hello Community,

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 ( 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.

Thank you!


Everyone's tags (1)
Community Member

I have this same problem

I have this same problem using only sip trunks from flowroute cannot park transfer or hold calls without losing audio and this is only for incoming calls if I call out it's fine and if call internally this works.  My only option at this point is to go back to nextiva which was my last sip trunk provider but I have to pay 30 dollars per line only one channel each.

Community Member

Yes, this is happening with

Yes, this is happening with incoming calls only on my end as well.  Have you asked flowroute to investigate this issue when it happens, and did they reach the same conclusion? Have you contacted Cisco about the issue, or do you have a support contract with them to begin an investigation into this issue?  I'd much rather get Cisco to fix this problem rather than switch carriers or go back to land line.  Perhaps we can work together and share any fixes we find.  I made a call today to check on support contract prices.

Community Member

Any update or resolution on

Any update or resolution on this?  I am having the same problem.

Community Member

nope gave up and went back to

nope gave up and went back to pot lines, I tried nextiva sip trunks and those did work but at a higher price than I wanted but they do give resellers 100 dollars per line you setup.  The problem with them is once every few days the phone system would just stop receiving calls and have to be rebooted.  I tried calling cisco to get access to the advanced menu config but they will not give out that access so nothing more could really be done maybe there is a another sip provider that works but I can't try them all out.

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