On Fri, 06 Mar 2009 18:04:04 -0500, Don Wilhelm wrote: >If I recall, the signaling has been tested out to 6 feet of cable, but >it sounds like your plans will require more cable length than that.
The primary issues with cable length are noise pickup and capacitance. Both can be helped a lot by using CAT5 for the serial connection. Dedicate one pair to each signal line, and connect the return of each pair to the connector shell, not pin 5. CAT5 is very low capacitance, and the very high twist ratio rejects noise and RFI. Going to the connector shell bypasses the pin 1 problem at each end. I work in pro audio, and we often have sound equipment in racks buried in the bowls of the building, but need to remote control that gear for tuning the system from within the auditorium. Doing what I've described, we often use serial over 200 ft of CAT5 at very reasonable data rates with no problems. BTW -- the RS232 standard originally quoted cable length as a limit, but was later revised to define it on the basis of capacitance. 73, Jim Brown K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
