The topology is as follows:
CCM---WAN---Voice Gateway with E&m E1 --->PBX
The voice gateway is configured as H.323 gateway on CCM. If a user behind CCM 4.1 tries to call a user behind the PBX it is successfull.
If a user behind the PBX tries to dial a user behind CCM the user's phone rings and once he picks up the handset he hears two beeps and then the lines drops.
I have checked the codec and it is the same on both sides.
I appreciate any thougts on this issue,
Remark: The E&M E1 is using immediate start signaling