URC can tell hai what to do all day long. RS232 is the way to do it. Anything HAI can do, URC can tell it to do that. Having HAI tell URC what to do is a whole different story. Possible, but more complicated.

You have a spare Ethernet? That will work even at two different location as long as you can get from the HAI to the URC.

As far as UPB goes, you will have MUCH fast response by having URC talk directly to UPB and not go thru the HAI. Use a PIM or CIM and have URC talk directly to UPB via RS232.