phone wire paradox

"Tip" and "Ring" don't have any real significance anymore.... a phone line is just a "pair". ...Jim Thompson

But you live in another time ;-) ...Jim Thompson

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Tip and ring have significance when my touch tome phone merely clicks instead of dials.

Digital services provided by the likes of one's cable company likely do not have any such paradigms in place.

I think it is so the lightning arrestor works properly.(the reason it was originally used).

The cable guys have their own protections in place for that, and no "battery rooms" to deal with. Since ours is fiber, there are probably no line extender power supplies on the hard line runs either, since the 'hard line' is now fiber.

Oh, really! Then why is there 48 volts off hook and a polarity "spike" when the caller hangs up? ..and related always to Tip and Ring inexactly the same way since Ma Bell was alive as _one_ company?

But the polarity of the 48 volts and the off hook spike is only significant at the central office. It doesn't matter at the phone. The spike polarity is generated relative to the loop polarity as seen at the CO.

There is one exception to this. Back in the 'old days' when touch tone phones first came out, there were a few implementations where the phone circuitry was polarity sensitive. The phone could answer calls when the polarity was reversed. But it would not generate touch tones. I'm sure Ma Bell fixed this little bug rapidly, as it generated quite a few complaints and service calls whenever they'd do some line splicing and get a few loops backwards.

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You're being too charitable. When I got my touch tone phone, they had been in common use for some 15 years, and switching tip and ring still disabled dialing.

It works to this day, although from time to time I have to tune up the oscillator slugs, to accommodate more sensitive "Press 1" systems.

Most non-AT&T phones, long ago, put a bridge around the dial to solve that problem. Perhaps AT&T liked service calls.

Today with almost all phones using a diode bridge, polarity isn't very important at the customer premises. However, the good old mechanical ringers were polarized so that the inductive kick when hanging up the phone didn't generate a "ding" with the bell. The British were so upset by this bell "tingle" that they wired their phones with 3 wires, so that the bell would not be across tip and ring when the phone was going back on-hook. Take an old mechanical ringer phone apart and you'll see the clapper for the bell has a stop on one side to prevent the "ding".

Clearly the receiver and the carbon transmitter didn't care, nor did the hybrid transformer...

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Oddly back in those days, the phone company would sometimes switch your polarity AFTER you're connected, which meant that some people could NOT use the touch tone as a reply!

Dial using the hook. ;-)

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Reread, I said AFTER connection. You have no idea how frustrating that polarity switch was to people accessing pager systems and/or their banks.

But it is interesting that one can STILL dial a phone by tapping the cradle hook

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I read it fine, but you weren't explicit. After you connect to the phone company they reverse it. I've never heard of the line reversing after you've dialed. How does that happen?

That's what I said. Rotary phones didn't care about polarity.

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It primarily to antique equipment that is still polarity sensitive. A solvable problem BTW.

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Yours has slugs? Mine was not tunable. They must have spent more on = mine to get that repeatable of inductors.

?-)

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That was for the pay phones, to know that the other end has answered.