sundance-communications.com/forum Forums Wiring - Telecom Carriers - Trunks & Services Cabling Telephones Systems Wiring pinout on pots line with rj 11 or rj 14

This might be a dumb question, but due to the recent post regarding wiring of the pots, I begun to being bothered with the same question again and again that I was long time ago.

The question as follows: Why does the pinout of the cable is reversed on both ends?

Just by looking at it, it is not hard to figure out the intention of keeping the wires of the same color/pin running continually even after it went through a coupler connecting together two rj11/rj14's.

As we know that it is not the case with rj45 cat3 and up types of cable, where pin 1 is to pin1 wiring scheme.

I guess I would like to know more info on it as maybe a history of it goes, and possibly a standard of it back quite a few decades ago.

Looking around google didnt produce much useful results, nor that I want to sip through goofy results, such as this Video , maybe they do things way differently in UK :bang:

That's why I am seeking an answer and a bit of history here from the pros in the industry. :bow:

It was exactly as you stated, to keep them straight all the way through. Important back when polarity and party lines were issues.

So that the machinery would put the plugs on the same way, every time. The ridge on the cordage indicates to the machine operator that the cord is oriented correctly. It was an oversight, or a blunder, or just dumb bad luck that they needed to reverse the colors in the phone to compensate for the "reversal".

Later cords, as you point out, use a different method of assembly, with different (better?) results.

To me it seems that the 1 to 1 pinout is logical and insures that everything is wired correctly, and it also avoids confusion, because both ends are the same on the cable, unless otherwise needed like in crossover cables. And the needed cross connections to ensure consistency of pin 1 are incorporated into connecting equipment/jacks/hardware that is used to interconnect two cables together.

It does makes sense though in the machinery assembly part, fast, and easy.


What are the potential risks in reversing polarity, by say accidentally crimping the plug on one end incorrectly? Probably with modern equipment it'll still work as I have seen a MLX-10DP plugged in with rj11 50 and 100 ft cords.
What about residential phone and/or other consumer tel products?

No polarity risk at all for POTS anymore. They had to 'dumb-down' the system via reverse-engineering.

Basically, the manufacturers had to minimize the complaints about non-functioning equipment by making it not sensitive to polarity. What a sad state of affairs.

Not entirely true. Still needed for party lines (which still exist, in this day & age) as well as telephones that had polarity sensitive dials that are still in use as well.

Ridge, Right, Ring, Red