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From: varney@ihlpf.att.com (Al L Varney)
Newsgroups: comp.dcom.telecom
Subject: Re: Massive Service Outage in Northern Illinois!
Message-ID: <13945@accuvax.nwu.edu>
Date: 23 Oct 90 20:11:03 GMT
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In article <13789@accuvax.nwu.edu>, wmartin@stl-06sima.army.mil (Will
Martin) writes:

> 6) This was a pretty obvious situation; you've got a guy with a
> backhoe in open land with a big hole and two broken ends of cable
> sticking out.  Suppose the work had been done by one of those
> horizontal-digging underground-boring machines, putting in a drainage
> pipe or something, that chewed through the cable under an undisturbed
> surface, and the machine just chomped the cable like it was a tree
> root and continued on. No one doing the work might even notice. Now
> here you have "n" miles of underground cable, no obvious hole anyhere,
> and a break somewhere.  With copper wire, you can use time-domain
> reflectometry or something like that to get some idea of where to
> start looking, but can you do that with fiber optics?

Last question first: time-domain reflectometry has it's optical
counter- part -- a broken fiber reflects like a bad mirror.  Check out
the ton of ads in Telephony for fiber trouble-locating equipment.

As to non-backhoe fade-inducers, one of my Dad's neighbors had the
misfortune of killing a quarter-mile of cable connecting an old
previously-independent area with the rest of Southwestern Bell.

 The scene: A county (gravel) road in a lightly-populated area in Kansas.
   A recently-regraded ditch parallels the road, with a broken-down
   fence on the far side of the ditch.  Fence needs repair before
   cows can occupy pasture on far side of fence.
 
The solution: Build a new fence just inside the old one, leaving a
   couple of feet between fences to allow access to the "road" side
   of the fence.

The problem: When SW Bell bought out the Independent, overhead wire was
   replaced with underground cable and the cable was trenched inside
   existing telephone poles (which tended to be directly in line with any
   existing fence).

Since the post holes were dug to a depth about equal to the cable
depth, several dozen holes were in place before the auger pulled up a
good-sized chunk of cable.  Unfortunately, the cable was damaged in so
many places the whole distance was re-trenched, inside the new fence.
Note that there are (and were) orange poles placed near each
intersection of the cable and any public road, with a reminder that
telephone cables are buried nearby.

 Since the affected area has a population of about 70 farms, one
church and three businesses, the cable damage provided more coffee
break jokes than consternation.


Al Varney, AT&T Network Systems, Lisle, IL