The below is a forwarded AOL email from Chris Chapman


Hi Richard and everyone,

Following Bob's good advice, if you go to
http://www.arcelect.com/technica.htm
you will find specs for RS232, RS422, RS423, RS485, several other standards,
cable pin connections, trouble shooting software, other reference website
links
and even lightning protection advice.  I suggest they you 'Bookmark' this
extensive technical information source for future reference.

Getting back to cable runs, RS232 is nominally recommeded for up to 50 ft., 
although in favorable circumstances this can be extended.  RS422/RS423
nominally operate up to 4,000 feet.  For RS232, there are a number of
substandards with differing voltage lines, switch levels and deadband around
zero volts.  Long exposed cable runs often do need lighning protection /
surge
protection / opto isolation.

Regards, Chris Chapman   




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