The RS485 card must be installed in a period PC circa Windows 95 or Windows 98 with a
full length ISA slot plus one for a video card, so ideally two or three, see below.
The PC should be a basic model with no built in onboard features such as video card. I had troubles with conflicts on numerous PC's because even disabling the onboard features in BIOS or in Windows is no guarantee that
something else will not conflict. Reserving memory etc as stated in the manual is not a guarantee either. Sound/gaming port cards are also a no-no. LAN cards can also throw up problems.
Finding conflicts is frustrating. I bought two identical Windows 98 computers, one for my PC50 mill and one for my PC55 lathe. After spending many hours, disabling every onboard feature including video and purchasing
a video card I got the mill to work with its RS232 card. Mirroring the PC for the lathe with RS485 card did not work. I tried every combination that I could think of but to no avail. I bought another PC as above and it worked first time.
I had been lent compatible PC's for both the mill and for the lathe so I was lucky and could study the setup. The one for the lathe had gaming software and a joystick port on the serial card. That card had some keypress
conflicts with the keyboard but I could not take the card out because the PC would not boot without it. I did not want to completely reinstall software on a loan computer.
When searching for a suitable PC make sure the video port is on a card rather than grouped with the other outlets from the motherboard.
While I am no expert, it's my understanding that the RS485 card needs to be installed in a slot in the computer that has a memory address reserved or configurable for it.
Can anyone that has done this confirm or elaborate?
I have the manuals, but am away from home for a few more days.