Hello,

I fitted an extension socket and was reading which colour cable to
connect where. I was using wires with two pairs: blue/white and
orange/white pairs. I read that rarely a third pair (green/white) is
connected to terminals one and six. What were these used for and why
are they no longer used? I am guessing they were used for something
once upon a time otherwise they would not be there.

Thanks,
Stephen.

In article , Stephen
scribeth thus
Hello,

I fitted an extension socket and was reading which colour cable to
connect where. I was using wires with two pairs: blue/white and
orange/white pairs. I read that rarely a third pair (green/white) is
connected to terminals one and six. What were these used for and why
are they no longer used? I am guessing they were used for something
once upon a time otherwise they would not be there.

Thanks,
Stephen.

Http://www.telephonesuk.co.uk/wiring_info.htm

might help...
--
Tony Sayer

On Mon, 14 Sep 2009 15:06:20 +0100, tony sayer
wrote:


Http://www.telephonesuk.co.uk/wiring_info.htm

might help...


I'm afraid it doesn't. I had already found that site by google.
There's a lot of information there but all it says about the
green/white pair is:

"Terminal pins 1 and 6 may be absent on some versions of C/NTE5, but
these connections are not normally used anyway."

I notice all web sites say something similar "not normally used" but
they don't say "never used". This implies that occasionally they are
used but what for? And why do manufacturers spend money including them
if they don't have a use?

If I add any more extensions is it worth using 3-pair/6-core cable or
can I save some money by buying the 2-par cable?

Thanks.

On Mon, 14 Sep 2009 21:41:14 +0100, Stephen wrote:

snip

If I add any more extensions is it worth using 3-pair/6-core cable or
can I save some money by buying the 2-par cable?



2-pair is fine for normal extension sockets. As almost all phones now
synthesize the bell signal internally the terminal 3 wire isn't needed
either! You can just use a single pair.

The only time that you need additional cores are when you have some types
of PABX on your system. Details for connecting these will come with the
PABX - there isn't a standard AFAIK. Wire 3 is the "Bell" wire and is
used to stop other phones "tinkling" as a dial phone dials a number. It's
just about always redundant now (even though it's officially still part
of the spec).

Manufacturers have to make their connectors suitable for all the systems
that are out there - and they are standard connectors now. That's why all
the terminals are provided.

Don't be tempted to mix ethernet pairs with telecom pairs in the same
cable. You'll probably find that it's part-functional, and very annoying
to debug! It's just not worth it for the cost saved.

--
Mick (Working in a M$-free zone!)
Web: http://www.nascom.info
Filtering everything posted from googlegroups to kill spam.

On Mon, 14 Sep 2009 21:41:14 +0100, Stephen wrote:

On Mon, 14 Sep 2009 15:06:20 +0100, tony sayer
wrote:


Http://www.telephonesuk.co.uk/wiring_info.htm

might help...


I'm afraid it doesn't. I had already found that site by google.
There's a lot of information there but all it says about the
green/white pair is:

"Terminal pins 1 and 6 may be absent on some versions of C/NTE5, but
these connections are not normally used anyway."

They're actually used in my house!

My master socket used to be right alongside where the overhead cable
entered in the living room.

When I went isdn before ADSL, BT moved the master socket to the study
adjacent to the pc, and installed a secondary socket where the master used
to be, with a three pair between them. The green and white take the incomer
to the master on the three pair.



--
The Wanderer

Everyone brings happiness.
Some as they arrive, others as they leave.

Stephen wrote:
I fitted an extension socket and was reading which colour cable to
connect where. I was using wires with two pairs: blue/white and
orange/white pairs. I read that rarely a third pair (green/white) is
connected to terminals one and six. What were these used for and why
are they no longer used? I am guessing they were used for something
once upon a time otherwise they would not be there.

I believe that terminals 1 & 6 were for Telex.

See Table 1 of SIN 331, "BT 50 Baud Telex Service, Interface Description
& Withdrawal Notification", http://www.sinet.bt.com/331v2p1.pdf

You should be able to find the specs for pretty much anything related to
BT services on http://www.sinet.bt.com/

Rich.