I’ve installed the FreePBX image on a Rpi and have the PBX up and running. I would like to be able to have the PBX run in the background and launch the Raspbian desktop. I know the desktop is not included with the FreePBX image but is it possible to install it?
No, but the Raspbx image has both FreePBX and Raspian (not surprisingly - )
you can install any debian package presuming you have the repos defined, after the fact but this has nothing to do with FreePBX, just start over or get out the manuals . . .
The PBX does not run in the background. FreePBX, manual or ISO install, wants full control of the system. It is needed for things that it can do. It’s going to want control of Apache, SQL, be able to write to the system, delete from the system, etc.
This isn’t going to be like launching some app on your desktop and then “backgrounding it”.