09-01-2004 01:24 AM - edited 03-13-2019 06:12 AM
Hi,
I have the following configuration using a CCM 4.0 and a cisco 3725 GW (with two E1):
PBX-Gateway-PSTN.
Everything work fine except calls to the PSTN from phones that are connected to the PBX. The call lasted 4s and disconnect.
RQ: the calls between IP phone and phones connected to the PBX are all ok.
Thanks for your support.
Patrick.
09-01-2004 05:13 AM
A debug isdn q931 should reveal the disconnect cause. Search for "isdn disconnect cause codes" on CCO and you should get a document which will help you decode the error code.
09-01-2004 07:35 PM
This is true and worth doing, but I'll go ahead and leap to a conclusion.
The ISDN debug is more than likely going to show a recovery on timer expiry. We're likely waiting on CONNECT_ACK from the PBX. This is ISDN timer T313 which defaults to four seconds, just like you're seeing. You would hear audio properly during this period. And if we're expecting/waiting on CONNECT_ACK, we're acting as the User side of the PRI. And if we're not getting it, the PBX is also acting as User side. One side needs to be Network and one side needs to be User.
If you run these debugs and verify this is the problem, you should configure the gateway as the Network side. If you're using H.323, set "isdn protocol-emulate network" on the Serial interface. If you're using CallManager/MGCP, you set it on the Gateway configuration page in CCMAdmin.
I'm trying to figure out how you could get away with calling back and forth properly between IP phones and the PBX; I'm not sure how that's working. Anyway, check out the top half of this thread below where another person had the same problem. There's debugs posted there which will hopefully match what you're seeing.
09-06-2004 02:26 AM
Hi,
Thanks for your replies.
I've already configured the "isdn protocole-emulate network" on the serial interface connected to the pbx.
I think the problem could be related to Timers ...
Yes, calls between IP phones and PBX-phones are working in and out.
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