I just switched to VOIP telephone service, and had to run an outside line
from where my cable service comes in to where the old POTS line comes in. I
used outdoor rated shielded cat3 cable and I've got it working great, but
I've got a couple of questions because I really, really like to know WHY I'm
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
Looking at my wiring, I see that my old outlets have only 2 connectors,
whereas the new outlets I purchased have 4 connectors. Should I replace my
old wall outlets? Is there any benefit if the voice quality is already good
as is? Do my telephones care?
Finally, is the old, thin telephone wire still considered adequate? I'm not
about to rewire this house, but I'd like to know if I do this again in the
in the words of the immortal Sgt Schultz:
No, unless they are not working or you need the practice.
24-gauge is the current standard. There is plenty of 26-gauge <gag> out there
but, other than its propensity to turn into a rats nest in a ready-access
cable terminal, it is technically sufficient for POTS.
I discovered the other day that Menards is STILL selling *GARBAGE* telephone
cable. It is white-sheathed 3-pair 24-gauge with (apparently) NO twist. The
"pairs" are red/green, yellow/black and white/blue.
Just to verify my suspicion, I connected my butt set to one pair then applied
my "toner" (tone generator) to another pair. The cross"talk" was so bad it
was almost like a direct/hard connection. Absolute trash for anything more
than one line. Talk about "let the buyer beware". Sheesh! :(
The "twisted pair" technology was developed in the 1920s, I believe.
In basic electricity, we learn that a conductor carrying a "flowing" current
generates an electromagnetic field around that same conductor. This is the
basic principle behind electromagnets and electric motors.
A phone line (a pair) generates an electromagnetic field. Another phone line
(pair), also generating its own electromagnetic field, when run along side
another, working pair, will inductively "cross" with that pair after only a
few feet of side-by-side operation.
It was discovered that, if each pair is twisted (perhaps 2-3 full turns per
foot, at least), and the entire cable is then twisted, the electromagnetic
fields "cancel out" one other.
You'll notice that old telephone cable has minimal twisting, but it's there
and is sufficient for POTS (Plain Old Telephone Service) including DSL.
Modern Cat3 cable is noticeably more twisted and Cat5e is twisted even more.
This is to improve the performance of the cable for data purposes.
The garbage wire sold by Menards has NO (zip, zero, nada) twist and, as such,
is unsuitable for anything more than ONE working POTS line - the extra
pairs/copper is just wasted. Simply put, it is substandard wire. If this
were electric cable, the NEC/NFPA/UL would jump on their @$$ in a heartbeat.
There's no code or legal requirement for minimal specifications for low
voltage communications cable. As such, Menards is getting this wire from the
cheapest vendor (no doubt China) and foisting it on unsuspecting DIYers that
probably believe they are installing "the good stuff" when finishing their
basement or home office. It's trash and Menards should be ashamed.
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 helped a friend upgrading to DSL, and found some old still plugged
in AC adapters for lighted phones buried in cielings of this over 100
year old home.
The upgrade was a nightmare since verizon did NOT like AT&T supplying
DSL on their network. I swear verizon did something intentially:(
I finally plugged the modem, directly into the NID and it wouldnt work
dependably, then tried my working modem from home, it wouldnt work
A week later my friend got verizon and it worked flawless....
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.
Additional pairs are for additional lines, dial light current (obsolete) and,
in the case of a failed pair, a SPARE pair that can be used.
The Bell System defined the term "overkill" as swatting flies with a
Even back when there were 2, 4, 6 or even 8 subscribers on a SINGLE pair, they
wired homes with two pair cable.
In the 60s and 70s they switched to 6-pair cable. (Serious overkill.)
Then, for 15-20 years, they backed-off to three pairs. The standard now is
4-pair and likely to be a standard for a LONG time.
It takes only a pair of wires to make a phone work. So what are all those
extra wires for? They're just... EXTRA!
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 were: green, green stripe, blue, blue stripe, orange, orange
stripe. I forget which ones were in use.
Those are indeed standard colors. 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.
I think I understand that system now. It would allow 25 unique
combinations. What do you do for more than that?
Anyway, this is not the same as what I found. This was just a 3-pair
cable, each pair has a solid color wire (green, blue, or orange) and a
white one WITH A STRIPE of that color. This house had just one line. I
forget which pair was used.
BTW, I have some new phone wire I got at Lowe's in October. The colors
are white, black, red, green, yellow, blue (that's the order they're
shown on the wiring diagrams on the package).Several places they said
the colors to use for phone lines were line 1: red/green line 2:
black/yellow, line 3: white/blue. The packaging for the jacks mentions
an alternate code, which is like what I found. I think your system was
an additional alternate, but I don't remember.
The first 25-pairs are spiral-wrapped in a white/blue "ribbon". The next
25-pairs are similarly wrapped in a white/orange ribbon. The third group (of
25-pairs) is wrapped with white/green ribbon. The ribbon bundling the 25-pair
groups follow the same color code sequence as the first 25-pairs. This works
up to 600-pairs. Beyond that, the sequence starts over with the addition of a
red ribbon to every 25-pr group. These are known as "super groups" to
indicate the count starts with pair 601.
You should see what it looks like when a backhoe brings up a 900-pair cable
the hard way. Thank God I'm not a cable splicer. Call before you dig.
BOCs (Bell Operating Companies) used 3-pair for probably 15-20 years. The
white/blue pair was used for line one and connected to the red/green posts on
the jack. The third pair (white/green) was used for dial light voltage and
laid down to the yellow/black posts. White/orange was just spare unless it
was used for a second line.
That describes exactly the garbage cable that Menards sells. I would hold out
for cable rated Cat3. I'm guessing there is no "cat" rating on your cable.
However, unless you're running more than one line on the cable (requiring only
ONE pair), rating or twist doesn't really matter. With tight/good connections
and insulated from each other and ground, one can run a POTS line on bailing
wire and coat hangars. More than a few DIYers do.
I've never been in such a situation (having to fix a broken 900-pair
cable). I can imagine what it would be like.
Several houses were built around there (Denton TX) at that time. I
don't know about the cable, but I do remember hearing other people
mention nonstandard cheap stuff being used.
I also don't know about the quality of the wire in the house I live in
now. It was built around 1969 too and has black/red/green/yellow wire.
I don't know about twist, and never had a second line using it. I have
had a second line, but that used separate, newer wiring.
Since the primary colors are white, red, black, yellow, and purple the
first twenty five pairs would have a white blue wrapper. The second
would have a white orange and so fourth. The sixth would have a red
blue wrapper. The seventh would have an red orange wrapper. The
eleventh would have a black blue wrapper. The twelfth would have a
black orange wrapper. So you have twenty five pairs times twenty five
wrappers for a total of 625 pairs. I never learned what the code is
What you describe as the colors you found is the first three pairs of
the color code system. All three pairs had the white primary color and
one of the first three secondary colors. As I said before if the
installer followed the drill; i.e. used standard practice; The pair
that was used for the first telephone line was the White with blue
stripe and blue pair.
The type of telephone wire that uses solid colors up to three pairs is
called JK or station cable. It usually has little or no twist to it so
if long lengths of it are used for two or three telephone numbers it is
prone to cross talk.
And a stripe (in the secondary color) on the white wire. Is that
I looked at the old phone wires (probably the original ones installed
around 1969) in this house. They are red, green, and yellow. No black.
Of course that doesn't really matter. They's need replacing if I
wanted to use more than that one pair.
When I opened that box (on the outside wall), it was nearly as full of
ants as was possible. This is not one of the newer NID boxes people
One apartment I lived in for a year or so around 1980 has a plug-in
transformer with its secondary connected to the extra pair
(black/yellow) or the phone wiring. It didn't seem to be used for
anything any more, but according to what I heard, it used to be used
for a lighted-dial phone.
BTW, for the 3-pair cable I've seen the additional pair is blue &
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