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Find out Which VCM is used

Find out Which VCM is used

Find out Which VCM is used


We have a issue on a customer, sometimes they can't hear the caller on incoming call.

They are using a siptrunk.
They only complain on incoming call.
We have taken traces between the ipo and the router, in that trace we can hear the caller and the callee.

Then we think the issue is on the ipo of network.

Actually direct media is enable, but in my opinion that can't be the issue as we have transcoding SIP/H323.

I think the issue may be the VCM, there is 1 combo and on VCM32 in the system.

Any idea if we can see in Monitor which card as been used for a specific call ?
If we always have the issue on the same card then this may be cause.

any idea how the ipoffice manage the 2 Cards Channel ? does it send a call to one vcm of to the other randomly of does it always use the first card and when this one is full to use the second ?


RE: Find out Which VCM is used

My understanding is that you cannot see which VCM is being used. If you are able to catch a troubled call live on system status (at the trunk level) then try and see if there is a common remote media server among the bad calls. Some SIP providers use a variety of remote media servers. You could simply be missing a route to one or one of the servers could be bad.

I also have never had a VCM provide true one way or no audio. VCMs typically just cause quality issues when they are bad.

RE: Find out Which VCM is used

Even if you go from SIP to H.323, RTP is still the same. It's only signaling that is changed.

You can see in System Status if it actually uses a VCM channel for the call or if it's relaying the RTP stream.

"Trying is the first step to failure..." - Homer

RE: Find out Which VCM is used

It always users the card in slot one first and then two and three. So if the combo card is in slit one then swap it with the vcm32 to see if it improves.


I'm not insane, my mother had me tested!

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