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H.323 Gateway between CME 10.5 and CUCM 12



I configured H.323 Gateway between CME 10.5 and CUCM 12, unfortunately I have the following challenges with calls:

CUCM to CUCM = Successful

CME to CME = Successful

CUCM to CME = Successful


CME to CUCM = Unsuccessful. for this, If I call from CME to CUCM, the phone registered under CUCM rings and when I answer the call, the voice is not passing through (If I answer call from CME to CUCM, there is no voice and calling phone i.e. phone from CME gives a busy tone after some 10 seconds. Note that If I answer call from CME to CUCM, the phone from CME still giving a tone that indicates the outgoing call then after 10 seconds it gives a busy tone).

Any documentation regarding this will highly be appreciated.

Your Kind support will highly appreciated

1 Accepted Solution

Accepted Solutions

Then it sounds to me like you have a problem with session progress messages being negotiated when CME calls CUCM. The CME is not receiving the H225 Connect message sent by CUCM when the call is picked up on the CUCM side, or CUCM is expecting H245 negotiation at call pickup which the router is not responding to. I'm thinking this is a mismatch between H323 Fast Start (on the router) and Slow Start (on CUCM).

On the CUCM H323 Gateway configuration page, in the "Call Routing Information - Inbound Calls" section, look for a checkbox "Enable Inbound FastStart". If that is not checked, check the box and reset the gateway and see if that fixes the problem.

If that doesn't work, we'd need to look at your config.


(But I'd still plan on converting to SIP at some point. It is your best long-term plan.)

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8 Replies 8

Chris Deren
Hall of Fame Master Hall of Fame Master
Hall of Fame Master

Why not use SIP? With the versions you listed it would preferred protocol, and troubleshooting will be much simpler.