Doorbox video while ringing

Has anyone figured out a way to see video from a Door Box on a phone while it’s still ringing? I’ve searched and found a lot of confusing and conflicting information but no straight answer.

Video is fine once the phone is answered. I need the preview video to show while the phone is still ringing.

I’ll give all the specs if it’s relevant but first, is this ever possible on any spec with any setting or is it universally not supported?


Asterisk is a back to Back User agent so an answer is needed You probably need a full blown SIP Proxy

It might need some coding: How to get video preview? - #27 by Summer - Asterisk SIP - Asterisk Community.
You can start tests by connecting doorphone directly to the phone, enabling direct ip calls on the phone if needed and searching for “early video” option and/or SIP answer code 183 in phone settings.
Some doorphones can call multiple destinations at once and sometimes PABX is not really needed.