Date: Thu, 4 Mar 2010 15:32:15 -0600 (CST) From: Robert Bonomi <bonomi@mail.r-bonomi.com> To: freebsd-questions@freebsd.org Subject: Re: RS232 / TCP converter and BSD. Message-ID: <201003042132.o24LWFhW018772@mail.r-bonomi.com>
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> From owner-freebsd-questions@freebsd.org Thu Mar 4 10:41:36 2010 > To: freebsd-questions@freebsd.org > Date: Thu, 04 Mar 2010 10:41:00 -0600 > From: Martin McCormick <martin@dc.cis.okstate.edu> > Subject: Re: RS232 / TCP converter and BSD. > > Chuck Swiger writes: > > Data centers use that for serial connections to stuff like Cisco routers > > and other terminal applications all the time. However, if the device is > > truly RS-232 rather than 422/423, it's nominally out of spec past 50 > > meters > > and possibly won't go past 9600 baud. > > I was wondering about that when I wrote my long-winded > response. I was confused and thought the maximum length for > RS-232 was longer than it is. 70 meters is almost 25% out of > range which is kind of pushing things. The 'standard' way to get around that distance limitation is to use a "RS-232 to current-loop" adapter, often referred to as a 'short haul modem'. see: <http://www.blackbox.com/Store/Detail.aspx/Short-Haul-Modem-Nonpowered-Async-SHM-NPR-DB25-Male/ME721A-M-R3>; for one example from a quality, but fairly pricey, source. Note: you need one of these on each end of the wire.
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