OXO and 3CX integration

[R4+Z]

Hi

Due to Covid 19 we had a number of customers rapidly switch to 3CX due to the ease of using a mobile app. Now they are returning to the office, we had the issue of them wanting to retain the mobile app but not have to replace the Alcatel desk phones.

After some messing around and an unusual way of solving CLI issues, I thought I would let people know that this can be achieved. There isn't any other feature transparency but CLI to show extension to extension numbering and both inbound and outbound CLI is possible.

[frank]

Did you use a basic sip trunk between the 2?

[R4+Z]

Yes, using IP registration. However I had to use two trunk groups on the 3CX in order to get the CLI to look right for internal calls but then use another trunk group to send a CLI that would allow me to transit the Alcatel for outbound from the 3CX. I found there was a way in the 3CX to modify the SIP header accordingly. I have to be careful what I say in an open forum as my employer may consider this to be intellectual property of theirs!

[frank]

I understand. No worries, changing the headers in 3CX is public source, and I've done it in a lab a while ago against OXE (not OXO).
Nothing of intellectual property here. Just smart people doing shit!

[giovanni.attolini]

The best way is put an asterisk between them and use bridge istead of sip trunk on 3CX side. Why an asterisk? Because you can treat CLI from 3CX that use "Remote Party ID" to send it. So 3CX <-> Asterisk <-> OXE or OXO is the best way. Using bridge you don't need treat incoming calls and the transit is transparent.