Hi,
>From the soap box of Teunis.
Never use 100BaseT ie copper cables between buildings even if they are only 50metres
apart.
WHY??
When you connect two buildings using copper you have the chance of tying them together
electrically. This can create a very dangerous situation. It is indeed possible to
have 50Kvolts sitting on a cable as the the electrical earths between the two
buildings can be different. Beleive me theere is nothing more frightening than
watching communications equipment disappear of a wall during a thunderstorm purely
because two building were tied together.
I think you'll find that in Australia for example the standards committees on building
codes now prohibit tying two buildings together with copper.
Companies such as Critec in Tasmania, Australia have made a nice little living on ways
to stop the linking of buildings.
Back in the good old days of pure serial comms I worked in a University and spent a
considerable amount of time trying to track down a suspected intruder that usually
operated out of hours in offices covered by security with terminals turned off. It
turned out to be earth loops. The cause running copper between parts of a building
that had different electrical earths.
My word is always run fibre when connecting two buildings.
I expect an argument that telcos do it and connection of modems is not a problem.
Modemd generally use either transformers and/or optocoupling to disconnect themselves
electrically from the line.
Teunis,
Tasmania, Australia
On Monday, December 04, 2000 at 05:20:06 PM, Hartnell. George wrote:
> Not with copper. Single mode fiber with LX modules work for me. You can
> buy 100Mb/sec cu to single mode fiber media converters. I don't think you
> can 'get there from here' with multimode fiber, or, as aforementioned,
> copper.
>
> Oddly enough, it seemed (to me) that gigabit LX gbic modules for some
> catalyst switches are just as inexpensive as the media converter lash-up.
> One-hundred meg ethernet is also less challenging to 'sniff' for problems.
>
> Probably you will want to run single-mode anyway; keeping future scale-up
> options open. Strandage? Spares are handy. Phones too? Look at copper
> hybrid cable for cu-T1 or extra fiber stands for T1/DS1 PBX phone switches.
>
> Or, why not wireless? If you're line-of-site, there are some 100Mb/s
> solutions out there.
>
> Best, G.
>
> -----Original Message-----
> From: Rossetti, Stan [mailto:[EMAIL PROTECTED]]
> Sent: Monday, December 04, 2000 3:10 PM
> To: '[EMAIL PROTECTED]'
> Subject: 100BaseT Between Buildings
>
>
> Does anyone know of a way to implement 100BaseT between 2 buildings that are
> ¾ (~ 4100 feet) of a mile apart? I think the distance limitation per
> segment is 200 meters.
>
>
>
>
> Thanks
>
> Stan Rossetti
>
> Russia Services Group
> Voice: (256) 544-5031
> Email: [EMAIL PROTECTED]
> Beeper: 544-5031 pin 0112
>
> CCDA, CCNA, CCSE
>
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