I am working a ticket with GS on this but I was curious to know if anyone else has seen this and / or has found a solution to this.
A few months ago we got in about 200 new GRP2615 phones in a couple of different shipments and we are seeing the same issue with all of the phones out of these shipments. On inbound calls there is an 8 second delay on the audio going back out to the caller. Outbound calls have no delay at all. All of the phones in question have a hardware revision of 2.1c, 2.1d, etc. If I put one of my much older Hardware Rev 2615’s on the same UCM there is no audio delay.
I have duplicated this behavior on several different UCM 63xx models, but it only seems to affect 63xx. And it has happened on every 63xx i have tried (About 10 at this point). It doesn’t happen on my 6510. The only surefire way I have found to resolve this issue is to put the UCM on 126.96.36.199 firmware. Any firmware newer than that has the delay issue and the firmware on the phone makes no difference.
I feel like this might be a NAT issue but I have duplicated it behind multiple routers and multiple network setups at multiple customer locations. We are programming these UCMs the same way we have been for years, the only difference is the Hardware Revision on these phones.
Like I said I am working with GS on this and I am providing them captures, I’m just curious to see if anyone else has experienced it because it’s pretty easy for me to duplicate on any 2.1 Hardware Revision phone.