nicoll wrote:
I have found RJ45 plugs to BT sockets which would allow me to plug a phone
into a RJ45 outlet. But at the panel end I want the opposite a BT plug to
RJ45 socket to fit in the BT socket so I can then patch to the panel. Do
these things exist or is there and easier way to achieve what I want.
Been there, done that. My magic formula goes like this: use the LAUs
you've found - RJ45 plug one end, BT socket on the other - at the
'office' locations. LAU, meaning I think Line Adaptor Unit, is what the
structured-wiring wallahs sell for this job; you want the 'totally
plain', passive, flavour, not the 'master' or 'secondary'.
At the phone incoming location, I made up a compatibly-wired
BT-plug-to-RJ45 socket, by butchering a couple of BT-to-BT leads and a
couple of RJ45 patch cables; joint made using small terminal block
inside an adaptable box (3 incoming lines here - 2 over HomeHighway, one
'ordinary' taken post-filter ADSL (so I have only one filter, in the
master socket, and take all the extension lines including the one going
to the patch panel on the filtered side - saves all that fannying about
with microfilters; I also feed the ADSL side, which my master socket
offers on an RJ11, into another of the structured-wiring ways. (As Bob
Eager pointed out, RJ11s go into the middle 4 of an RJ45 by deliberate
design.)
'Compatible' above just means that the combination of the LAU wiring
(for which there's no accepted standard, so buy several of the same make
in one go!) and the homebrew cable, when joined 'straight-through' over
any number of RJ45 patchleads, acts like a simple BT plug-to-socket
extension cord. A coupla minutes with a multimeter sorts out the
necessary wiremap.
OK, that's the phone-input side and office-output side. At the patch
panel, I use 3-way RJ45 all-female couplers to feed the phone signal to
as many 'output' drops as makes sense: 3-way because each one other than
the first and last has two 'bus' connections and one 'drop', if you see
what I mean. If your patch panels aren't too dense, you can instead use
a one-male two-female RJ45 adaptor and plug that straight in to the
patch panel.
I hope if standard parts are available I won't have problems with connecting
the correct pairs.
Sorry, but I think you'll have to accept one bit of homebuild wiring for
the BT-plug-meets-RJ45-plug bit, because (a) LAUs vary, and (b) in 'real
office' installs, they punch phonelines directly into fancy-pantsy
structured wiring feedpoints which cater for many (12? 16?) incoming
lines at a time. If you don't have crimp tools for both RJ45 and BT
sockets, as most of us don't, chopping into presupplied cables is the
way to go; be warned that UK phone-style cables are often wired in
weirdo (litz?) wire - hard-to-connect-to copper strands interwoven with
a fibre substrate of some sort, which you won't be able to solder to -
fold it back on itself once or twice before using a suitable pressure
connection.
HTH - Stefek
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