Please don't flame me but I don't have a clue about ModBus. I was given the job of creating an interface between a washing machine and a Sco Unix OpenServer 5.07 server through a serial port….. That was my brief. I discover I need to use ModBus protocol to manipulate the register on the controller a bit more complicated but I’m not too scared yet… Can I first check I’ve got the right idea, there’s a serial port on the control you connect via a serial port with a client package (logon) then peek/poke away? Is there a client package for SCO? If not is there a windows PC copy? I would really appreciate some advice. I have downed some ModBus documents any suggestions or URL’s to read up on are also welcome.