Why can't I use a standard 9-pin serial I/O cable when programming Whedco servo drives from my laptop? I can only get the genuine Whedco serial cable ($$$$) to work, and not give errors.
I would bet the manuals would tell you what the pinout is, or even if it is not RS-232. It is not unheard of for manufacturers to supply a cable that has some kind of built in converter.