When someone activate call forward (*72) to an external number (cell phone), he can see only the outgoing trunk phone number instead the original caller. It makes sense for me, because the pbx do a calling out on another “line”.
It would be nice, that the cell phone user can see the original number, but how can I configure the freePBX that it sends it back to the VoIP provider (with a 302 or “Refer”, is that correct???)?
It depends on a couple of things in your configuration:
If you have your trunk set up to always set the caller ID to your number, it will override the callers CID.
If your provider doesn’t allow “foreign” caller IDs, they could be setting the CID for you. Some providers just block the call if they don’t allow foreign CID, others will quietly reset it to “the correct” caller ID.
Assuming you don’t have either of those things, the CID from the original caller should show up on the external phone.