You're right of course. But I'm really reluctant to send out a RS-485 system based on my own experience with the termination problems. Its also harder on the end user because they will need a 232 to 485 converter for each network. I should probably do some reading, but I would think I could get an RS-232 chip and tri-state the drive to high Z, and thereby effectively allow multiple units to sit in parallel. The down side is that I haven't found any 232 recievers with a high input Z. They all seem to have 5K by design.

John