Dear Group:
This may be a stupid suggestion, but what if one were to install optoisloators on the cable line? This would short-circuit (literally and figuratively)what the cable company can detect? Or is there something I have not thought of?
Glenn
Electronics_101@... wrote:
Message: 5
Date: Mon, 29 Mar 2004 00:51:53 +0100 (BST)
From: signal snatcher <signalsnatcher@...>
Subject: Re: Re: what can the cable company detect?
Phone companies use a technique called "Time Domain Reflectometry (TDR)" which is a type of radar. It can be used on any type of cable and optical fibre. Its very accurate, down to a centimetre or so. It can tell if the line has taps, bridges, extensions and what type of load is at the other end.
It s comparatively easy to make up a TDR; Google should have any number of sites. You do need a CRO though and a lot of practice.
If you are checking any type of cable TDR is the way to go, so I imagine that's what cable TV companies use. In Australia the phone companies run cable and broadband and phone companies have seen _everything_ in the way of illegal use and faults, so you can't put much over them. On the other hand every phone company seems to have the attitude that customers are either thieves or idiots so they never take your explanantion for anything.
Dave Mucha <dave_mucha@...> wrote:
--- In Electronics_101@..., Albert van Mil wrote:
I had a problem years ago with the phone. We were billed 10 times
as high as usual, so something went awry. Asking the phone company,
they told they could detect how many phones were connected in our
house and they just said they detected only one and no further
problems.
We wanted an investigation so they came... It turned out someone cut
our phonecable and put his phone on it, outside the flat, and had
lots of
expensive calls. Later on he just soldered (PbSn) a piece of cable
to cross
the cut to establish the connection again. We didn't have to pay
the bill
Conclusion: they can't detect what's happening, although they say
so.
They can
do so if there is a nice homogeneous cable but not anymore if there
are
connectors (with their resistance), soldered cables, wires mounted
by
screws etc.
Albert
I had a problem years abgo (before digital cable) with the phone company. The told me they wanted to run a diagnostic and then in less than a minute, told me the problem was something like 3,127 feet and 11 inches away from the central office. the next day the repair truck came out and stopped just around the corner, put up a ladder and found the problem. Since she said I was something like 3,321 feet and 7 inches from the central office, they knew exactly where to look.
But our Church had gotten some huge calls and teh phone company couldn't find anything. One of our guys went out to the phone box and found it was loose. Then kept an eye out and a few nights later found a guy using alagator clips to tap into our phones.
Guess they have some idea what is going on.
Dave
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