George Cutsogeorge, W2VJN, firstname.lastname@example.org, mentions that flat 4
conductor telephone wire is available for $0.02/foot as part number 630-0630
from MECI at (800)344-4465.
R. E. Smith, Inc. at (513)874-4796 has volunteered to provide two pairs of
their RS-232 to RS-422 converters for evaluation on the Easter Island and
Heard Island expeditions. We will try to run between tents with RS-232, but
if we get in trouble we can switch to RS-422. Ron has been VERY supportive.
Fred Lucas, K1EFI, Fred_Lucas/Marketing/GDC/US.GDC@noteshub.gdc.com, who is
the chairman of the Telecommunications Industry Association (TIA) standards
committee TR-30.2 which is responsible for DTE/DCE interfaces including
RS-232 which is now officially called EIA/TIA-232-E reports:
>Your reference to 50 feet is an old misconception on the limit for 232. In
>early version of 232, up through 232-C, the distance was specified as
>up to 20 kbps over a cable capacitance of 2500 pf, typically 50 feet. Many
>users of 232 took this to mean 50 maximum when, at the time of that writing,
>it was typical. Since the -C version, we removed all reference to any typical
>distance. The present version of the standard, EIA/TIA-232-E, provides some
>guidance as to how to determine maximum cable length based upon cable
>capacitance. In today's world, cable with 10 - 12 pf per foot is common so
>operation at 200 - 250 feet at 20 kbps is very reasonable. As with any
>standard, it has to be written for worst case applications. I have seen very
>successful operation of 232 installations at much greater distances,
>at lower data rates.
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