The DLV11-J has a ten-pin connector. To use with RS-232, simply use pin 2 as ground, pin 3 as TxD, and pin 8 as RxD. It is also necessary to jumper pin 7 to pin 9. The reason for the jumper: the receive input of the DLV11 is differential: it could work with RS-422 as well as RS-232. RS-422 uses two wires for Tx and two for Rx and these are differential ... it is the polarity of the lines relative to each other that sets the bit (whether it is a one or a zero). These "twisted pair" signals are very immune to noise and are used industrially for long runs. I was always taught that anything over 20 feet should _not_ be RS-232 but a differential standard instead. Anyway, grounding the "minus" differential receive input makes the "plus" differential receive input single-ended so that it is now referenced to ground: a voltage on that pin "positive" with respect to ground is a zero while a voltage which is "negative" is a one. This is the EIA standard used for RS-232 ... it is bipolar (i.e. the voltage can swing negative or positive with respect to ground). So, for a small system where the terminal is close, RS-232 works fine and a simple cable will suffice. Where a system is large and terminals are placed a fair distance from the machine, RS-422 should be used. Professor Mark Csele, P.Eng. Niagara College, Canada 300 Woodlawn Rd., L-23 Welland, ON, L3C 7L3 (905) 735-2211 x.7629 E-Mail: mcsele at niagarac.on.ca URL: http://technology.niagarac.on.ca/people/mcsele Author of "Fundamentals of Light Sources and Lasers", Wiley, 2004