External calls with Dead Air

[richdaniels]

We have an issue that has been occruing for about 3 weeks now. Nothing has changed on our network. We are running a single 3300 with a combination of 5312, 5324, and 5330 IP Phones. The 3300 is currently on V5 SP2. I have had our phone provider check there cnnections to us, we use 2 T1 PRI's, everything on there end checks out. The issue is intermintely we will make a call, or recieve a call and on party or the other gets dead air. One person can hear everything, the other hears nothing. On outgoing calls you never hear the phone ring or anything, but the call is completed as the other party can hear fine. this also occurs on our ACD calls. Any suggestions of what I can look at?

[ralph]

What kind of trunks are you using?  PRI, SIP, Copper?

If you make 100 calls, how many fail?
Do you ever hear ringing or just on some calls?

Ralph

[martyn]

Depending on the type of connection as per Ralph's question as to whether a CCS trace or a tcp dump might be required to troublshoot.

[richdaniels]

We have 2 PRI's.

I would say roughly 20 out of every 100, give or take.

When this occurs it is dead air, no ringing, no nothing. It's like the handset or headset was never picked up.

[ralph]

This could be a couple of things.
Let start with the easy things first:   Reboot your 3300.

Next do a couple of test:  Make ~10 calls into one of your own DID.   See if you get any failures.  If not make 20 more just to be sure.
Then call somewhere else.  Could be a cell or someones home.  ~10 calls.   
Then call someone long distance.   ~10 calls.

What you're looking for is to see if you can narrow down failures to LD calls, local calls or calls within your own CO.

Next, have your carrier work with you to trace a failed call.   Too often when you report a problem to a carrier they will just check the T1 for error.  That's not the problem here.  You need to specifically request to work with a switch tech to do call traces to isolate the cause of the one way audio.  They will monitor while you make enough calls to create the failure and then they can more closely ID the cause.   It may be something as simple as a protocol mismatch.

Although it is possible that you may have a problem with a DSP, it wouldn't be my 1st choice.   A reboot may resolve that in any case.

Also, as martyn suggested, you can turn on traces in the PBX. 
The command is 'ccs trace en cont'.
Make a phone call and dupe the issue.
To turn off the trace 'ccs tra dis'

You can post it here if you like.
I'm not an expert at reading the traces but there some people here I think can.

Ralph

[richdaniels]

3300 has been rebooted.

Problem calls are not specific to anything, occurs on any and all calls, Local, LD, Cell, etc. However, they do not occur internally.

I have our carrier doing a trace now on some calls I have provided.

Patiently waiting on carrier.

[richdaniels]

New info related to this issue.

Our normal dead air call came through the system to an ACD Agent. One of the managers happened to be on silent monitor on the call. The manager could hear both parties when the agent had nothing but dead air. The tells me the issue is internal, thoughts?

[v2win]

Since you have two PRI's if they are in the same trunk group from the carrier and if you have the capacity available can you unplug one of the circuits and see if the problem goes away with either circuit

[richdaniels]

Thanks for your help. It has been traced down to the E2T2 processor. We are having it replaced tomorrow.