RE: BT to RJ45 convertors

["Keith Doxey" <ukha@xxxxxxxxxxx>]

> I've often seen them labelled as Master, Secondary & PABX so
I assume
> the PSTN reference is actually a Master version. Keith would probably
> have the definitive answer though...
>

Is this where I come in then :)

> You'd use a Secondary adaptor after plumbing in your master socket
> into the patch panel - in the same way you'd install a Secondary
> socket from B&Q as an extension of your master socket (if you
hadn't
> embarked on this whole UKHA / Cat5 escapade.... ;-)  )
>
> PSTN? Maybe if you didn't have an NTE5 faceplate (master socket), just
> a wiring junction box and you wanted to relocate the master socket
> elsewhere (master socket includes some lightning protection and
> separates out the ring signal IIRC).
>

A PSTN version will be a MASTER which means it will be fitted with a 1.8uF
capacitor for the ringing and should also contain a 470K resistor betweent
he bell wire and A wire. This allows BT to test that the line is making it
all the way to the telephone (theoretically!). It may or may not contains a
surge arrestor

> PABX - to be used with a PABX (!) IIRC some PABXs make use of 6-core
> "BT" cable in place of the more normal 4-core. Maybe the
adaptors have
> 6-core cable/pins?
>

Usually a MASTER but without the resistor or surge suppressor. Used for
ANALOGUE TELEPHONES on a PBX. PBX's that use system phones almost always
require a SECONDARY.

If you start with a MASTER you can convert it to anything you like by
snipping out the components. You can use a MASTER in place of a PBX adapter
with no problems whatsoever. The only reason the resistor and surge
arrestor
are not fited is to save money as they are not needed, but they wont do any
harm by being there.

To convert to a SECONDARY just snip out the resistor and capacitor. You can
leave the surge suppressor (if fitted). It wont degrade anything but may
help when storms are around.

Not the use of the word "MAY" as nothing affordable can protect
against a
direct or very close surge.

Keith