Hello all. new to the site. I've checked the archives, and the forums, now I'll ask the experts. Have a Symax 300 PLC and original Compaq programmer. The boss wants all the different PLC's software on a PII laptop so we don't have to use multiple computers. The old comaq is on it's last legs Apparently, there is an interface card in the compaq, an SFI323, and it's an RS422 port. Naturally, the laptop only has an RS232. Anybody got any ideas on how to interface the laptop to the SYMAX? Thanks for your help in advance, I look forward to hearing your ideas. DJW