On May 2, 2006, at 6:07 PM, Vasile Surducan wrote:

>> rs232 isn't spec'ed for 500m of cable.
>
> are you sure ? which specs do you have ?
>
Well, for instance:
    http://www.lammertbies.nl/comm/info/RS-232_specs.html

Max speed 20kbps, max drive capacitance 2500pf (which is about
50m worth of CAT5...)  To go 500m, you'd supposedly have to run
somewhat below 4800bps.

I don't know if there's been any formalization of the modern
DB9, 115200bps, etc world...

http://en.wikipedia.org/wiki/RS-232C has some of the issues
highlighted...

BillW
-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist