I just had to fire off that post quickly. Probably too late, but I didn't want to delay.
First, welcome to the Forum !
The 8-pin "RJ-45" style plug on the 1747-AIC labeled "Peripheral" is not an Ethernet plug. It is the same physical style, but A-B and other manufacturers had been using those for different purposes long before twisted-pair Ethernet came along.
Instead, it's a Data Highway 485 network plug. And because some devices that connect to it (like the old 1747-PIC) require power, it has +24V power on Pins 3 and 8.
That +24V can damage an Ethernet port if you connect that port to an Ethernet device. It's not guaranteed to do so, but it's possible.
To connect a PanelView Plus in place of a PanelView Standard on DH485, the best approach is to replace the 1747-AIC with a 1761-NET-AIC, or to add a 1761-NET-AIC just to serve as a converter/isolator for the PanelView Plus RS-232 port.
What other devices are in your network ?