I will be easier to get a concierge key and leave the present key on the voicemail PC.
We have one site still running on one PC and using 4b software. You can use 4b on your present system. We can also handle the upgrades. I still question the ivpc board on the concierge system. I think a dealer may have done that to get a few more IST ports for room phones. It would be better to put 8101 Comdial phones in the rooms using digital ports. E-mail me if you want us to upgrade your site.