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Re: DC fiber cut: field report
From: "Jay R. Ashworth" <jra () scfn thpl lib fl us>
Date: Sun, 20 Jul 1997 12:14:54 -0400

On Fri, Jul 18, 1997 at 06:44:21PM -0400, Robert E. Seastrom wrote:
   Am I the only one who's a cables and switches weenie enough to know
   that the telco's _already do this_?  Large numbers of local multi-pair
                                                           ^^^^^^^^^^^^^^^^
   trunking cables are pressurized with nitrogen, and they put pressure
   drop alarms on them, so they know if one takes a hit.

pressurized nitrogen is usually done to keep moisture out, not so that
they can monitor pressure loss.  pressure loss in a fed, very long,
pipe is an extremely local phenomenon anyway.  i think there are
spooks at some black agencies that monitor against tapping this way.
but in practice, nitrogen pressurization is only done for copper.

Yes.  I know.  ;-)

I'm told they really do pressure loss monitor the local stuff, though,
even if more for dryness purposes than cable-break.

Cheers,
-- jra
-- 
Jay R. Ashworth                                                jra () baylink com
Member of the Technical Staff             Unsolicited Commercial Emailers Sued
The Suncoast Freenet      "People propose, science studies, technology
Tampa Bay, Florida          conforms."  -- Dr. Don Norman      +1 813 790 7592


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