"Dennis G. Rears (FSAC)" <drears@pica.army.mil> (08/11/90)
I just had a second line installed in my house. I had to do some of the wiring which is now finished. I do have some basic questions that came out of it though: It seems as if each telephone cable contains four wires (red, green, black, and yellow). For one line only the red and green wires are used. The black and yellow wires are only used for the second line. If only one line is installed in a jack why do the yellow and black wires have to be attached? I suspect it doesn't. The modular jack that goes into the phone has four wires in it. Why is that, if only the red and green are required for service? Just in case you have a two line phone? Why is the jack that goes from the telephone headset to the telephone a different size than the jack that goes from the phone to the wall jack? Is it to idiotproof the process? Also why four wires into the headset? Does the phone itself do anything to the signals before it sends it to the headset? If the proper size jack was put on the headset could you plug that into the wall jack and recieve calls? What do the two wires (red and green or yellow and black) carry? Is one postive and negative like electrical wires? In the case of my second line I bought a double wall phone outlet. I installed the first line (R&G) to the top outline and installed the second (B&Y) line to the bottom outlet. The first line worked the second did not. The second line was live as I have a jack wired right into at the NIU. I then disconnected the wires from the NIU for the first line and reconnected them to the NIU for the second. That got the second line working. That says to me that there must be something physically wrong with the Yellow or Black wires. That seems strange to me as all four wires are in the same cable and if there was a physical break in the cable it would affect all the wires, not just one or two. Any thoughts of this? Thanks for any help. Dennis P.S. Does anybody know the number for ringback for 609-871-XXXX?
John Higdon <john@bovine.ati.com> (08/11/90)
"Dennis G. Rears (FSAC)" <drears@pica.army.mil> writes: > If only one line is installed in a jack why do the yellow and > black wires have to be attached? I suspect it doesn't. Generally that's true. In the olden days, the black/yellow sometimes served as the means to power the lamp in an old princess or trimline phone. In the REAL olden days, there was no black wire and the yellow wire was the ground, useful for party line service. > The modular jack that goes into the phone has four wires in it. Why > is that, if only the red and green are required for service? Just in > case you have a two line phone? This is one reason. Another would be for the A/A1 control for a key telephone system. If one adds a single line phone to a standard 1A2 key system, it must have a separate off-hook indication. > Why is the jack that goes from the telephone headset to the > telephone a different size than the jack that goes from the phone to > the wall jack? Is it to idiotproof the process? Also why four wires > into the headset? Does the phone itself do anything to the signals > before it sends it to the headset? If the proper size jack was put on > the headset could you plug that into the wall jack and recieve calls? Absolutely not. Believe it or not, all that stuff in the phone base actually serves a purpose. Besides the obvious, such as ringing and dialing, the base contains a "hybrid" circuit which takes the two wire phone line and converts it to a "four wire" circuit for the earpiece and for the tranmitter (microphone). It also provides a small DC polarizing voltage for the transmitter that is derived from the power in the phone line itself. Oh, and yes, the jacks are a different size for the purpose of idiotproofing. > What do the two wires (red and green or yellow and black) carry? Is > one postive and negative like electrical wires? Not LIKE electrical wires, they ARE electrical wires. Remember, electricity, not sound, travels through wires. Your voice is transformed into an electrical representation which is actually carried through the wires. > That says to me that there must be something physically > wrong with the Yellow or Black wires. That seems strange to me as all > four wires are in the same cable and if there was a physical break in the > cable it would affect all the wires, not just one or two. Any thoughts > of this? Long distance speculation of your problem would be difficult, but even if you get the line to work, you might want to replace the wiring with "twisted pair". The wire you describe, commonly called "D station wire" does not have the working pairs twisted. This almost invariably creates crosstalk between lines. Time and time again, there are people in this forum complaining about their modem line being heard in their voice line, etc., etc. The cause is usually traced to the fact that they are running two phone lines through D cable. What you want is "E wire", where the pairs are individually twisted. This often comes in three-pair and can be spotted by the colors: white/blue; white/orange; and white/green. I have E wire running all over the house, with modems, voice telephones, stations, and trunks all intermixed therein. There is no crosstalk whatsoever -- not a trace. Consider yourself lucky that there is something wrong with the D wire. Take the opportunity to pull it out and replace it with the right stuff: E wire. BTW, E wire comes "jacketed" and "unjacketed". Mine is all jacketed, but you can save a little money with unjacketed if it will run in a concealed place such as through the wall, in an attic, or under the house. John Higdon | P. O. Box 7648 | +1 408 723 1395 john@bovine.ati.com | San Jose, CA 95150 | M o o !
Dave Levenson <dave%westmark@uunet.uu.net> (08/11/90)
In article <10692@accuvax.nwu.edu>, drears@pica.army.mil (Dennis G. Rears (FSAC)) writes: > It seems as if each telephone cable contains four wires (red, > green, black, and yellow). For one line only the red and green wires > are used. The black and yellow wires are only used for the second > line. If only one line is installed in a jack why do the yellow and > black wires have to be attached? I suspect it doesn't. The extra wires are installed for ancillary services. This may include a second line, a lighted dial, a ground lead (used for selective ringing and party identification on multi-party lines). On new service, these days, they install four-pair (eight wire) cable -- it's cheaper to put in extra wires at the time of the initial installation than to put them in later, when the customer needs them. > The modular jack that goes into the phone has four wires in it. Why > is that, if only the red and green are required for service? Just in > case you have a two line phone? See above. > Why is the jack that goes from the telephone headset to the > telephone a different size than the jack that goes from the phone to > the wall jack? Is it to idiotproof the process? Also why four wires > into the headset? Does the phone itself do anything to the signals > before it sends it to the headset? If the proper size jack was put on > the headset could you plug that into the wall jack and recieve calls? The handset has four wires -- a two-wire circuit for the microphone, and another two-wire circuit for the receiver. Your line from the central office, as you have already noticed, has two wires. The bidirectional audio signals on these two wires are separated by a circuit called a hybrid, located in the telephone instrument. It separates the transmit and receive audio information and provides the derived four-wire path to the handset. > What do the two wires (red and green or yellow and black) carry? Is > one postive and negative like electrical wires? The two wires deliver DC power to operate your telephone set. They also carry AC voice signals. The red wire should be at ground potential, and the green wire should be at -48 volts. > In the case of my second line I bought a double wall phone outlet. I > installed the first line (R&G) to the top outline and installed the > second (B&Y) line to the bottom outlet. The first line worked the > second did not. > wrong with the Yellow or Black wires. That seems strange to me as all > four wires are in the same cable and if there was a physical break in the > cable it would affect all the wires, not just one or two. Any thoughts > of this? If you wired the B-Y pair to the red and green terminals on the second jack, then you probably have an open black or yellow wire in your cable. If the B-Y pair is connected to the black and yellow terminals on the second jack, connect it to the the red and green terminals on the second jack, and it will work better. It's not unusual for one wire to become defective in a multi-wire cable; that's another reason why they install extra conductors. > P.S. Does anybody know the number for ringback for 609-871-XXXX? I suggest that you try 550-XXXX, 551-XXXX, 552-XXXX etc. XXXX would be the last four digits of your telephone number. If you get a busy signal, try the next one in the sequence. If you get a dialtone after dialing, flash your switchhook. If you then get a high tone, hang up and your phone should start to ring. To stop the ringback, just answer and then hang up for at least ten seconds. Dave Levenson Voice: 908 647 0900 Fax: 908 647 6857 Westmark, Inc. UUCP: {uunet | rutgers | att}!westmark!dave Warren, NJ, USA AT&T Mail:!westmark!dave
roy@alanine.phri.nyu.edu (Roy Smith) (08/12/90)
John Higdon writes (Vol 10, Issue 560, Message 2 of 3) > The wire you describe, commonly called "D station wire" does not have the > working pairs twisted [...] What you want is "E wire", where the pairs > are individually twisted. The untwisted wire described is what I have always called "quad station wire", I have no idea what the real name is, but I don't think "D station wire" is right. My AT&T catalog lists what they call DIW, "D Inside Wire" which is indeed twisted pairs. You can get it in various pair counts from as few as 2 or 3 up to, I think, about 6 or 8. The most common variety I've seen is 4 pair. Unlike common 25 pair cables, the pairs are packed loosly in the PVC sheath, making it very flexible. It sounds exactly like what John is describing as "E wire". I am willing to defer to hard evidence to the contrary, but I have trouble believing you could get any appreciable amount of crosstalk between two properly balanced circuits (even if not using twisted pairs) over the, say, 100 feet of wire you might find in a common residential installation. My trailblazer coexists just fine with my voice line over plain old quad wire, running what I would guess is about 60 feet in the same quad. In theory, I would agree, you want to run twisted pairs if you have the choice, but if quad is already in, I wouldn't bother replacing it for plain voice or voice-grade modems. Roy Smith Public Health Research Institute 455 First Avenue, New York, NY 10016 roy@alanine.phri.nyu.edu -OR- {att,cmcl2,rutgers,hombre}!phri!roy
julian@bongo.uucp (Julian Macassey) (08/12/90)
In article <10692@accuvax.nwu.edu>, drears@pica.army.mil (Dennis G. Rears (FSAC)) writes: It's Deja-vu telecom time again. > It seems as if each telephone cable contains four wires (red, > green, black, and yellow). For one line only the red and green wires > are used. The black and yellow wires are only used for the second > line. If only one line is installed in a jack why do the yellow and > black wires have to be attached? I suspect it doesn't. You are right, a telephone line requires two wires or "one pair" in telco speak. The first pair are the Red and Green and the second pair are the Yellow and Black. For a one line installation, you only need to connect the first pair (Red and Green). The second pair is often not connected through anymore - standards have gone to hell since divesture. The telco used to connect the second pair (Yellow and Black) when installing so that if they popped in a second line they wouldn't have to hunt round the premises to splice all the second pairs. > The modular jack that goes into the phone has four wires in it. Why > is that, if only the red and green are required for service? Just in > case you have a two line phone? There are several reasons for this besides a second line. At the end of this posting I am including something I posted in November 1988 in response to an inquiry just like yours. > Why is the jack that goes from the telephone headset to the > telephone a different size than the jack that goes from the phone to > the wall jack? Is it to idiotproof the process? Also why four wires > into the headset? Does the phone itself do anything to the signals > before it sends it to the headset? If the proper size jack was put on > the headset could you plug that into the wall jack and receive calls? Because it serves a completely different purpose. It idiot proofs it to some extent. But I have had customers plug the handset into the line jack and then call and complain that the line cord wont plug into the handset jack - this really has happened. Notice that a handset jack has and uses two pairs (four wires). It uses two wires to talk (Transmitter) and two wires to listen (Receiver). Ok, so the line jack is two wires (talk and listen on the same pair) and the handset has split talk and listen into separate pairs. Inside the phone instrument there is a device called a network that magically sends the voice signals to the right place. Yes, you could Micky Mouse a handset to work directly on the line, but the line voltage would soon kill the receiver magnet and the sound of your own voice would blow the wax out of your ears etc. So that is what the instrument stuff is for, if it wasn't needed, someone would have been selling handset to line cord adapters years ago. The Linesmans "Butt-set" has the network built into the handset as does the AT&T Trimline phone. > What do the two wires (red and green or yellow and black) carry? Is > one positive and negative like electrical wires? Yes, as a phone line is about 48V DC when "on hook" (hung up) and between 3 and 9V DC when "off hook", there is a DC voltage there. The normal voltage polarity is Green = + and Red = -. Some phone systems will reverse the polarity when a call goes through (rare these days). If the polarity is wrong, no biggy, some old 2500 sets may no longer dial, so flip the Red and Green and everything will work again. They phone wires also carry audio signals, Voice and Touch Tone. They also carry the ringing signal 40-150V AC. > In the case of my second line I bought a double wall phone outlet. I > installed the first line (R&G) to the top outline and installed the > second (B&Y) line to the bottom outlet. The first line worked the > second did not. The second line was live as I have a jack wired right > into at the NIU. I then disconnected the wires from the NIU for the first > line and reconnected them to the NIU for the second. That got the second > line working. That says to me that there must be something physically > wrong with the Yellow or Black wires. That seems strange to me as all > four wires are in the same cable and if there was a physical break in the > cable it would affect all the wires, not just one or two. Any thoughts > of this? Yes, you could have a break in just one wire in a cable. This is not uncommon. I have had this happen with long runs of cable, this is a good reason to install more pairs than you need. If you have a "bad pair", just mark it as such and progress. But as you are a domestic installation I would physically check the wire from the NIU (Protector) to the jack. There may be a connecting block or jack along the way that has not spliced the Black and Yellow pairs. One word of warning. Some lazy installers will often place the Black and Yellow under a screw in a a junction box/jack but will not strip the wires. It will look like two wires are connected under a screw head, but as they still have insulation, they are not. And now if you are still fascinated by all this stuff, here's more of the same. This is a posting from a couple of years ago that kinda covers the same ground. Newsgroups: comp.dcom.telecom Subject: The other pair of wires. Message-ID: <telecom-v08i0175m01@vector.UUCP> Date: 9 Nov 88 10:11:08 GMT Sender: chip@vector.UUCP Lines: 54 There has been a fair amount of discussion about what you will find on the second pair of phone wires in a residence. Here is a list of what you might/could find: The first pair will always carry a regular phone line. These wires are usually Red and Green, they can be White with a Blue Stripe and Blue with a White stripe. They are referred to as Tip and Ring. The Green or White/Blue wire is Tip and the Red or Blue/White is Ring. Tip is Positive and Ring is negative. ( Yes I know the voltage thingy is more complex than that, this is not for experts. For folks with Rat Shack meters, what I have said is true) Ok, now the first pair is out of the way, let's look at the second pair. They are usually Black and Yellow or White/Orange and Orange/White. These wires can have several things happening to them, but not all at once. First of all, there can be nothing on the wires, and they may not be connected anywhere. Next, the Yellow wire can be grounded. This is rare these days, but you will find it on old installations. Another old thing you will find is AC voltage for lighting the dials of old Princess phones. If you look around, you will find a wall transformer wired into the Yellow and Black wires. If the transformer says, "Bell System Property" etc. That's it. If you no longer have a rotary dial Princess with a lighted dial, pull it. Talking of old, old style multiline "business" phones. Yes, the ones with the buttons that light up and flash, they needed a hard wire signal to know that a line was off hook. This was known in "Telco speak" as "A-Lead control". If a single line phone was used as an extension on one of these systems also known in "Telco speak" as "1A2", the second pair (Yellow and Black) were shorted together when the phone went "off hook" to let the system know that a line was in use so all the right blinky lights came on. If you used a phone without A-Lead control, it went into hold when you hung up - most inconvenient. These days, if the telco uses the second pair, it is usually for a second line. Looking back to the first paragraph, the Black wire is Tip and the Yellow wire is Ring, usually known as Tip 2 and Ring 2. Yup, that makes the first pair (Red&Green) Tip 1 and Ring 1. Now, when discussing PBXs and modern "Key Systems", the second pair can often carry "data", stuff controlling the phones. More details available upon request. Available for Bar Mitzvoth weddings and barbeques. Julian Macassey, n6are julian@bongo.info.com ucla-an!denwa!bongo!julian N6ARE@K6IYK (Packet Radio) n6are.ampr.org [44.16.0.81] voice (213) 653-4495
John Higdon <john@bovine.ati.com> (08/13/90)
On Aug 12 at 10:31, Roy Smith writes: > I am willing to defer to hard evidence to the contrary, but I have > trouble believing you could get any appreciable amount of crosstalk between > two properly balanced circuits (even if not using twisted pairs) over the, > say, 100 feet of wire you might find in a common residential installation. I have seen it happen over lengths of as little as 25 feet. Remember that crosstalk rejection between circuits depends on the electrostatic and electromagnetic cancellation caused by the two conductors of the circuit. If you have conductors randomly interspersed within a cable and if an individual leg of one circuit travel for some appreciable distance with the leg of another, then your "properly balanced circuits" might just as well be unbalanced. > My trailblazer coexists just fine with my voice line over plain old quad > wire, running what I would guess is about 60 feet in the same quad. In > theory, I would agree, you want to run twisted pairs if you have the > choice, but if quad is already in, I wouldn't bother replacing it for plain > voice or voice-grade modems. That's very nice. Random chance works in mysterious ways. The original poster indicated that there was some hard problem with his quad. Rather than nurse it back to health or replace it with more quad, my suggestion was to replace it with the "right stuff". I have a number of "cheap and dirty" tricks that I use and get away with, but don't don't usually advocate them in a public forum. The "I know it's wrong in theory, but it works fine for me" principle can cause people grief. Once again, I don't recommend using quad (or any non-twisted pair) cable for multiple lines. I have seen the results and they are bad. John Higdon | P. O. Box 7648 | +1 408 723 1395 john@bovine.ati.com | San Jose, CA 95150 | M o o !
"Craig R. Watkins" <CRW@icf.hrb.com> (08/15/90)
In article <10881@accuvax.nwu.edu>, Julian Macassey <julian@bongo.uucp> writes: > You are right, a telephone line requires two wires or "one > pair" in telco speak. The first pair are the Red and Green and the > second pair are the Yellow and Black. For a one line installation, you > only need to connect the first pair (Red and Green). During the 70's (days of four-prong phone jacks), Rochester Telephone seemed to wire most (single-line) phones with the Yellow/Black positions on the jacks. We all assumed that this was simply to discourage would-be amateur telephone installers. I've never seen the non-standard wiring on RJ-11s unless there were two lines involved. Craig R. Watkins Internet: CRW@ICF.HRB.COM HRB Systems, Inc Bitnet: CRW%HRB@PSUECL.Bitnet +1 814 238-4311 UUCP: ...!psuvax1!hrbicf!crw
David Brightbill <djb@fsucs.cs.fsu.edu> (08/16/90)
My first experience with troubleshooting telco lines happened in a hotel during a tradeshow around 1975 or so. I was selling PLATO connect time and had brought a terminal to show off the system. The local telco supplied a phone instrument and jack (old four prong) which worked fine. When I plugged in my DAA (had one mounted in a briefcase with a trimline phone and transfer switch), I had a dead line. Of course, Southern Bell had supplied a line with the black/yellow pair live and had switched the lines on their instrument so that it would work.