The old criteria was 50 feet, but that was set before the specification for any
twisted pair for digital, let alone Cat 5. In short, it it works well, it is
OK but 200 feet sounds reasonable. RS-232 uses a 5 volt signal level. RS-422
uses a higher signal level, I believe 12 volts, but that is from memory. Watch
out for the serial dongles that plug into USB ports. Some are not full RS232
and do not work except with certain connections, ham radio applications not
included. Be careful and if it does not work, keep trying different dongles or
get on the internet and find the brand and source for one that will work. If
all else fails or if you want to be sure, buy a card based RS-232 or 488
interface that uses all DB-9 or DB-25 connectors. Willis 'Cookie' Cooke,VP of
Tidelands ARS and TXPE K5EWJ & Trustee N5BPS
From: Jim Brown <[email protected]>
To: [email protected]
Sent: Thursday, January 21, 2016 12:44 PM
Subject: Re: [Elecraft] Long RS232 Runs - RS422
On Thu,1/21/2016 10:32 AM, Michael Walker wrote:
> I wanted to mention that for those that want long RS232 runs for devices
> (Steppir, Rotator, Elecraft Amp),
It helps to define "long." Distance for RS232 was originally defined in
feet. Many years ago, it was redefined in terms of capacitance between
conductors. Using cables as common as CAT5, lengths of 200 ft or more
are no problem. Simply use one pair per signalling circuit.
73, Jim K9YC
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