David Woolley wrote: [] > When used with proper balanced drivers and receivers, twisted pair is > often better than coax. > > For any type of cable, group delay characteristics may be more > important than characteristic impedance match.
Whilst I agree with both points, for carrying what are TTL-level signals with rise-times probably greater than 100ns where you are using an RS-232 receiver to detect pulses 0.2s wide, and over a distance or 30m (i.e. a time of around 100-150ns), almost any cable will do. The only exception I might make is where the environment is electrically noisy - i.e. an industrial setting or running behind a photocopier, air conditioner, heavy motor or similar, where I would want at least shielded cables. I say this from years - too many years! - experience with RS-232. Cheers, David _______________________________________________ questions mailing list [email protected] https://lists.ntp.org/mailman/listinfo/questions
