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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] RE: Structured wiring -> BT Secondary skts
Title: Message Plugging a phone into a hub should cause any
problems
as most hubs have transformers on the RJ45, however plugging a phone line
into a
network card or hub would not be a good idea.
The
main A&B wires would be on the blue pair which is not used for ethernet
but
the ringing circuit is on the orange pair which is one half of the ethernet
circuit. Depending on the polarity of the line, there could be -50V DC on
the
wires.
Basically, if the kit is well designed it should
tollerate the wrong thing being plugged in especially as the phone line
cannot
supply more than about 50mA. Its a different matter if you have something
actually feeding a power supply onto the cable which is why I have
frequently
made mention of the requirement for fusing. Some ISDN circuits carry 48V dc
on
the Brown Pair.
The
ONLY downside of using RJ45 for everything is the possibility of incorrect
connection. The advantages offered by a common infrastructure far outweigh
the
risk of mis-plugging. In the 5 years that I looked after the Customer
Centre at
work we had over 600 circuits on our patch panel carrying a mixture of
.....
PSTN
telephone lines
ISDN
lines
Analogue PBX lines
Digital PBX lines
10
baseT ethernet
100
baseT ethernet
VideoOnDemand (ADSL type of delivery)
Lutron
Graphic Eye Keypads including power feeding
AC4600
audio conferencing unit
KAT5
AV distribution
KAT5
CCTV distribution with Power feeding
KAT5
VGA
and
several other Demo's that people turned up with that used unknown (to us)
electrical signals over a CAT5 connection medium.
Colour
coding some of the source sockets on the patch panel can help as can the
use of
coloured patch leads, details of the colour code we had as shown
below....
GREY =
a patch cord
Light
Grey = a different make of patch cord
<anything other than grey> = a cord we must have nicked from
somewhere
As you
probably guessed, we were only supplied with Grey cords but they did have
coloured labels on the ends.
Green
= Network
Red =
ISDN
Blue =
PBX
Despite people plugging stuff in whenever they wanted to, I never
had
anything damaged by incorrect connection.
IMHO,
there is probably less risk involved with structured cabling than there is
of
plugging the wrong WallWart into the wrong piece of
equipment.
Keith www.diyha.co.uk
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