<<< EISNER::DJA1:[NOTES$LIBRARY]TELECOMMUNICATIONS.NOTE;1 >>> -< TELECOMMUNICATIONS >- ================================================================================ Note 17.1 Two-line wiring that works... 1 of 5 EISNER::BRUCE "Barton F. Bruce - CCA/MA" 58 lines 3-APR-1990 18:38 -< black=green=TIP, yellow=red=RING >- -------------------------------------------------------------------------------- > My original thought is "it doesn't matter", but I seem to recall > having problems with a swapped red & green causing a Touch-Tone > keypad to cease working after a connection was made (back in the > old pre-access days)... You recall correctly. Back then most TT phones were polarity sensitive and to further complicate matters, not all ringing (especially on party lines) was just across the line at 20hz. The phone co installed everything (they thought) and so could control how every thing was wired. Most any phone you get today will have 'polarity guard' built in. This originlly was just a full ave bridge rectifer that made sure the TT pad got fed correctly. Another annoying 'feature' of phones is that if they are wired backwards, and if you ringer bias spring is set to the low notch because you are the tenth farmhouse served off the same 5 mile span of barbed wire and that is the only way the ringer will even ring, the ringer may also tinkle or tap for each number dialed. Dial 3 and you get 3 taps. Correcting the polarity cut the tapping. That is mostly history, and customers are NOT allowed to do their own wiring on party lines. The 'TIP' side of your line is essentially at ground and is +, and the 'RING' side is at -48. Tip is green and ring is red. For the second pair tip is balck and ring is yellow. if your wiring uses another color code (as it well may, especially if you have 2, 3, or 4 pair, as opposed to vanilla quad) the collors will be a subset of the standard 25 pair system that might as well be listed completely. I call them TENS UNITS to make it simpler. white blue red orange black green yellow brown violet slate The Tip wire of a pair will have a TENS body color and a UNITS tracer. The Ring will have the same colors, but be reversed body and tracer colors. The first five pairs use WHITE with the 5 UNITS colors in order. The second five use RED, etc. The first pair is the white/blue one, and white body and blue tracer is TIP. Pair 12 is black/orange. Pair 25 is violet/slate. But back to your problem. As carefull as you may want to be, it is very common for the telco types to not bother to get THEIR colors right, so be sure which is T and which is R on their side. You can generally pull a noisy dial tone between Ring and local ground, and, given the polaritys and grounding above, you can devise other tests. Dialtone from R to ground is valid also for a PBX's ground start CO trunk. If someone wants to know about ground start, and if we don't have a note on it somewhere, we can do that, too.