NEC 9100 In-Mail with PVA

[mikew1948]

Customer states PMS integration was working but disconnected it.
Now they want to restore it.
They have a PVA Blade and VM (GCD 16 VM00)
All licenses for Hotel, PVA, PMS are installed (no LUA)
They also have IN MAIL which seems like for Admin phones and Auto/ATT.
All hotel extensions are CF to a VE 275 which I think was the pilot for VM00
The extension 275 is now CF to In-Mail pilot, which they may have set when they disconnected PMS.
There is only one Dept. Group (64) for In-Mail
I’m thinking to get the Guest mailboxes working I need a Dept. Group forVM00 extensions which I assume was there when the PMS was connected and working.
Prog 15-55 has address for VM 10.2.112.211, 255.255.255.0
PVA 10.2.112.190, 255.255.0.0.
Looks likes hotel features are programmed.
Reading the Hotel manual I need to connect a serial cable between PVA and VM Blade for the VM to build and tear down Guest mailboxes.
Can the PVA communicate with VM blade via LAN or MUST it be via serial port?
Can I use the In-Mail for guest mailboxes and disconnect the VM Blade?
Any help, tips or suggestion would be greatly appreciated