OK, this is a long shot...

I have an old Axxess system still in use. I'd like to see if I can get dialing-from-pc working.
I have an executive deskset with a PCDPM installed, and a serial port on the PC. The PC is Win7, but I won't rule out setting up XP in a Virtualbox VM if necessary.

Does anyone know if it is *possible* to construct any CTI/PC dialer environment anymore? I do not have any security key for any of the old Inter-Tel software, so I can't install the tapiservice provider program. I was hoping that it would connect the Windows Dialer program, but I can't make that work.

I realize that this isn't something normal individuals would pursue, and there's no official channel for anything Inter-Tel anymore, but can anyone offer any suggestions? Barring that, does anyone know the RS-232 protocols to control a deskset from a PC?

I really appreciate any light anyone can shine on this old workhorse.