Routing Calls from one SIP trunk to Another SIP

[denniszitha]

I have one 3cx PBX on on end and Cisco call manager on the other, Cisco is connected as a SIP trunk in 3cx. I would like Cisco users make direct calls through another to via 3cx but it's proving to be difficult to achieve this please help

 

[leejor]

Do a search, there are a number of posts from users attempting to bridge a Cisco Call manager and 3CX. Unfortunately, I can't recall one without issues of some sort. It would seem that Cisco is not designed to be bridged to another PBX. But...you may have better luck.
Here are some..
https://www.3cx.com/community/threads/help-trunk-between-3cx-and-cisco-ucm.46979/
https://www.3cx.com/community/threads/3cx-to-cisco-ucm-bridge.68058/
https://community.cisco.com/t5/ip-telephony-and-phones/cucm-11-5-sip-trunk-to-3cx/td-p/3043547

 

[JohnS_3CX]

As a basic guide, you can look at the article for bridging with asterisk, which although not specific to Cisco, the bottom of the article gives you a good explanation of what 3CX expects to see in the SIP messages. If these requirements are met then you can pass calls across the two ends

https://www.3cx.com/docs/