Re: Submission for mod.telecom

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Article #747

#747

From: gary%percival%reed
Date: Fri, 20 Mar 1987 01:32

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There are several methods used by the telco's for line testing.  The simplest
is that all cables have a known (very precisely) resistance and capacitance per
foot.  If a short is applied at the end of a cable (or a known resistance, etc),
then a calibrated ohmmeter can tell you how far away the short is.  If you are
looking at a clean open, you can apply the same principle with a capacitance 
meter (though, in practice, it is not as accurate).  By knowing WHAT is hanging on the end of your cable, you can quickly tell the status of the pair AND the 
station.  This is why the telco's fought so hard about registration.  They 
really didn't care about the equipment, they just need to know what it "looks"
like, for trouble isolation purposes.

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References: <8703130415.AA22972@seismo.CSS.GOV> <17897@ucbvax.BERKELEY.EDU>

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Path: arc1-ca.pugleaf.net!utzoo!utgpu!water!watnot!watmath!clyde!cbatt!ucbvax!tektronix.tek.COM!gary%percival%reed
From: gary%percival%reed@tektronix.tek.COM.UUCP
Newsgroups: mod.telecom
Subject: Re: Submission for mod.telecom
Message-ID: <475@percival.UUCP>
Date: Thu, 19-Mar-87 20:32:55 EST
Article-I.D.: percival.475
Posted: Thu Mar 19 20:32:55 1987
Date-Received: Sun, 22-Mar-87 18:18:45 EST
References: <8703130415.AA22972@seismo.CSS.GOV> <17897@ucbvax.BERKELEY.EDU>
Sender: daemon@ucbvax.BERKELEY.EDU
Reply-To: Gary Wells <reed!percival!gary%tektronix.tek.com@RELAY.CS.NET>
Distribution: world
Organization: Percy's UNIX, Portland, OR.
Lines: 10
Approved: telecom@xx.lcs.mit.edu
Summary: Telco line testing stratagies

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