Call transfer UCM6204




I installed VoIP as architecture in the attached picture. I have a problem with call transfer. When an external number call me, sometime I found a block when I made a transfer for this call to room 100. Not all, some external numbers I can transfer it some others external number I can’t.

How can I handle this problem??


Can you explain what is meant by a block?


Maybe the call still on hold, not will be transfered


Then would it not go to voice mail? What do you hear, what indication on the phone? What kind of transfer, blind, attended, etc.?


It still hear the hold music, and that for any type of transfer


Let’s try this again-

A call comes in and is routed to the 2170. You answer and the caller then indicates they want to speak to extension 100. What exactly do you do to try and transfer the call to 100?


I made a bind to 100 or I choose the second (attended call) then I forworded to 100. But the same problem


On the PBX, please do a network capture while repeating the same transfer of a call and PM me the zip file of the capture.


Does a regular call from the 2170 to ext 100 work?

If yes, when you do the attended transfer does the initial connection work and just the transfer part break it?

What firmware are you on?


I can’t do a capture


On the UCM under Maintenance–>Network Troubleshooting there is an Ethernet capture.


Not a regular call to ext 100.
It’s a regular call for differents extensions. And when I made the transfer for the same external number to differents extensions, I had the same problem.


What firmware is the UCM running?


You can find in attached the capture. In fact I made a two calls. The first number was transfered but the second no. The call was from ext 10 to external number and then I transfered it to ext 45. (4.1 MB)


For the second number when I made a transfer(failed)42523215_253331785341884_1301911519218368512_n , I was capture what the ext 10 shows on the phone. The picture in attached.


For the second number when I made a transfer(failed), I was capture what the ext 10 shows on the phone. The picture in attached.




This picture is was after I made a transfer


A couple of things first.

You need to change the codecs in the UCM trunks, UCM extensions and the GXW.

The first one, in your case should be g711a and then g729. Get rid of all the others. The phone call is coming in as g711a and then the transfer is being handled as g711u to the GXW.

The GXW firmware needs to be updated, It is from 2015.

The GXP firmware needs to be updated as it is and the current one is

Then we can test.


Firmwares alone could fix your issues. I’d do the codecs as described as well.