On Tue, 13 Feb 2007 07:43:12 GMT, Thomas Horne
wrote:

Mark Lloyd wrote:
On Sun, 11 Feb 2007 22:59:46 -0500, mm
wrote:

On 11 Feb 2007 21:41:02 GMT, Bert Byfield
wrote:

Many years ago I did the telephone wiring for most of my house, and
although I connected all 4 wires I thought that only 2 carried the
line. So, 4 wires = 2 lines. Is it true that now each line uses all
4 wires? If so, what's different?
Phone lines use two wires. The second pair of wires was in olden times used
for an a/c connection to a phone accessory, but that never got very
popular. Some people used the second pair for a second phone line. Usually
the second pair is unused.
I always thought the 2nd pair of wires was there primarily for a
second line or any other use that might be thought of in the future,
the same reason my house built in 1979 has something like 6 pairs of
wires. Not because I'm going to have 6 phone lines but because the
phone company plans ahead. For the same labor, they can install more
than 2 connectors.


The house my parents bought in 1969 (it was a new house then) had the
phones wired with 6-wire cable. There was just one active phone
connection (hardwired then, in the kitchen), but wires were run to the
bedrooms so jacks could be added. It did not use the standard colors.
I remember when I tried to add another jack, I had to test it. The
wires we green, green stripe, blue, blue stripe, orange, orange
stripe. I forget which ones were in use.

Mark
Those are indeed standard colors.

Yes. I learned that LATER. At the time, the only standard I knew about
was red/green, black/yellow (and maybe blue/white).

Cables such as 3, 4, 25, 100, or 1000
pair use a repetitive colour code based on a primary and secondary
colour. The pairs are twisted together individually. There are only five
primary colours and five secondary colours. The 1st pair would be
White-Blue , the 2nd would be White-Orange, etc. The standard secondary
colors used in three to five pair cables are blue, orange, green,
brown, slate. If the original installer followed the drill he used the
blue and blue white pair for the first line. The white is the primary
color that identifies the first five pairs of the cable.
--
Mark Lloyd
http://notstupid.laughingsquid.com

"Unlike biological evolution. 'intelligent design' is
not a genuine scientific theory and, therefore, has
no place in the curriculum of our nation's public
school classes." -- Ted Kennedy