Typically, 50 feet is the maximum length for reliable communications over RS-232. Some laptop PC’s use the low power, low emission RS-562 instead of RS-232. With RS-562 your cable run will be much shorter than with RS-232. You can use a low cost RS-232 buffer/repeater amplifier to extend both RS-232 and RS-562 maximum cable lengths. There are many manufacturers of these types of products. Here are links to a few US sources:

B & B Electronics
R. E. Smith
Integrity Instruments

Third Party Product Disclaimer – From time to time we test the compatibility of our own products with those of third parties. While we are happy to share with our customers the results of our own studies as well as other (possibly unsubstantiated) information regarding these third party products, it is the policy of Symetrix, Inc. to neither endorse, recommend nor support products manufactured and/or supplied by third parties. The responsibility of choosing third party products which are compatible with Symetrix products rests solely with the qualified contractor, consultant or system designer.

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