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*************************************************************************** * * * The Telephone Works * * Egghead Dude * * CHiNA CHiNA * *************************************************************************** Welcome to CHiNA Educational InfoFile Series II, # 3. Once again, be looking for new files weekly for the next few weeks until school starts again. And contrary to Megaton Man's belief, we are still very much alive and in production. If he tells you otherwise, kindly call him a peasant and tell him to fuck himself...if you want. Enjoy! Here are the standards in Telephone Color Coding: Telephone circuits are paired as 'tip' and 'ring' wires. On POTS (plain old telephone service) tip is 0 volts and ring is -48 volts (tip is not 'ground' though as it is a blanced line). The pairs must be distinguishable from one another easily so they are colour coded. The colour of the wire indicates whether it is tip or ring. In a quad wire green and black are tip while red and yellow are ring. pair# tip colour ring colour _____ __________ ___________ 1 white blue 2 white orange 3 white green 4 white brown 5 white slate (silver) 6 red blue 7 red orange 8 red green 9 red brown 10 red slate 11 black blue 12 black orange 13 black green 14 black brown 15 black slate 16 yellow blue 17 yellow orange 18 yellow green 19 yellow brown 20 yellow slate 21 violet (purple) blue 22 violet orange 23 violet green 24 violet brown 25 violet slate An individual wire is identified by it's colour and the colour of it's stripe. The main colour determines whether it is tip or ring while the stripe identifies it's pair (i.e. a black wire with a blue stripe is tip of pair 11). In many cables the stripe is missing in which case the pairs are distinguished by the way they are twisted, by pulling back the sheath pairs are more obvious. As you can see there are only 5 tip colors and 5 ring colours (5 x 5 = 25). a 100 pair cable is made up of four of these 25 pair bundles. The first bundle is wrapped by a white/blue binder string, the second by a white/orange binder, the third by a white/green and the fourth by a white/brown. This scheme can be extended infinitum. Some folks think that the order is: Pair Tip Ring 1 RED GRN 2 YEL BLK 3 BLU WHT, and that the 1st pair was backwards in a modular connector compared to the rest. Wrong. The polarity is off. Modular connectors reverse the polarity so they make the issue pretty confusing. A modular line cord (that is a properly made _telephone_ line cord) has a flat topology such that when laid on a table the top of both connectors is up. This means that a reversal (polarity wise) takes place. Tip becomes ring on all pairs (the wire is a ribbon in theory). the top of both connectors is up. A 'set' jack (the one inside the telephone) is wired backwards to compensate. In addition, the system employed throughout the (used-to-be) Bell System was actually very simple. There wer five colors assigned to "tip" and five colors assigned to "ring". This gives a total combination of twenty-five pairs (very convenient!). The colors assigned to the "tip" are; white wt red rd black bk yellow yl violet vi The colors assigned to the "ring" are; blue bl orange or green gr brown br slate sl (sometimes mistakenly called gray) Standard phone convention is to identify the "tip" first and then the "ring" when referring to a pair. Thus, the first five pairs of a telephone cable are the "white" pairs; white/blue wt/bl white/orange wt/or white/green wt/gr white/brown wt/bn white/slate wt/sl The next five are the "red" pairs: red/blue rd/bl red/orange rd/or red/green rd/gr red/brown rd/bn red/slate rd/sl And so on, until all twenty five pairs are identified. What happens when there are more than twenty-five pairs in a cable? Simple, enclose each twenty-five pair group in a color coded binder. And guess what the color coding is for the binder. Yep, the same as the wires in the binder. The first binder group is the "white/blue" binder the second is the "white/orange" binder, and so on. If it is necessary to refer to the twenty-sixth pair of a fifty pair cable it is referred to as "two white/blue" or 2-wt/bl. The seventy-ninth pair in a one-hundred pair cable is called "four white/brown" or 4-wt/bn. This all holds true for the first twenty-four binders in a cable. The twenty-fifth binder is a little different, and my recollection is a little hazy but I believe the binder colors are white-white-blue. Yes that's two whites and a blue. It might be two blues and a white. It's been a long time since I was in a cable over six hundred pairs. One thing I know for sure is that they double up on one of the binder colors after the twenty-fourth binder group. There is also a convention for the positioning the pairs on connecting blocks. The Ring is usually on the Right and the Tip is usually on the Top. As you can see there is a pattern here, Ring-Red- Right and Tip-Top. I guess this was done to make it easier for us dumb installers to remember! |-) The only difference in the color coding between telephone cable (the stuff used outside and strung along poles or underground in conduit) and telephone inside wiring (the gray colored stuff in the walls and up in the ceiling) is that the inside wire has each pair traced with the color of its mate. That is, the first pair is a white wire with a blue tracer and its mate is blue with a white tracer. This is done to avoid "splitting" a pair. Splitting is getting the ring of one pair and the tip of another. In outside phone cable each pair is twisted with its mate and the chances of splitting a pair are not as great (although it's been known to happen ;-)). With wiring done inside a house, a little history is in order. Back when we had party-lines,(I know, we still do, but very few still in service and none available for new service) three wires were necessary because a ground was required to make the bell ring. So, the original phone wiring had three conductors, red, green and yellow. Red and green were ring and tip respectively and yellow was the ground. Then people started getting away from party lines and into princess and trimline phones with lights in the dial. The yellow was no longer the ground and a black wire was added and the yellow and black were used to supply power for the lamps from a small transformer. Time marches on, and now people are getting second lines installed in their homes. Since the new phones get the power for their lamps from the phone line directly, the yellow and black are now "spare". The yellow is usually the ring and black is the tip. Of course, houses that have been pre-wired with six-pair inside wire would normally have line 1 on the white/blue pair and line 2 on the white/orange pair. In many pre-wire installations I have found that the sixth pair (red/blue) was used for transformer power, although I don't believe that was ever an official practice. Written by: Egghead Dude Edited by: The Conflict Golf City BBS CHiNA Node #5 Hope you enjoyed this one, and once again, look for more! Please distribute this file freely, and if you really must speak to CHiNA, contact us on one of our member boards (a node list should be available wherever you receieved this file). Thanks for you support! A big HELLO to Mr. X, The Maestro, Barimor (hear you're doing wonders for the FiRM!), Jolly Green Giant, Feetsack, Lord Blix, Maxwell Smart, The Viper, etc...if you want to be said HELLO to, too bad, we don't like you! Really...we'll be seeing you!