Questions about polarity issues

[zuperdee]

Alright, the other day, I decided to try out some of my older touch tone phones that I haven't used in a while, and to my dismay, they showed signs of polarity reversal. I then did some checking, and sure enough, it seems that at some point, the polarity of the tip and ring on my line has become reversed. To make matters worse, I traced it, and it looks like the reversal is actually happening on the phone company's side of the wiring out in the street! My suspicion is that it may have happened during a major repair made after a severe storm we had a couple months ago.

I am assuming this polarity reversal would probably also explain why I've sometimes noticed a bit of bell tap on some of my older phones when other phones in the house are hung up, and for this reason, I'm tempted to demand that the phone company fix this in their wiring, but the questions is: How much good would this do?

My mom didn't even notice this problem with her old Automatic Electric AE-880 Touch Call speakerphone, because Automatic Electric Touch Call dials have ALWAYS had built-in polarity guards, unlike Western Electric. (Kudos to Automatic Electric for that!)

Anyway, it's really irritating me, because I've always tried to make sure that I have the tip and ring wired correctly when I do telephone wiring, and now it looks like not even the telephone company cares about getting it right anymore. So it raises the question: Should I give up caring, too?

Once a few years ago, before I learned about the polarity problem with touch tone dials, I discarded a touch tone phone that I thought was faulty. Today I really feel bad about that, because I feel like I needlessly destroyed a piece of history, and I wonder how many other old touch tone phones have similarly met such an undeserved fate. For this reason, though it may destroy their authenticity, I'm now toying with the idea of installing polarity guards in all of my older touch tone phones. Any thoughts on this idea? What's the best place to get polarity guards, and where can I get those orange insulating boxes that Western Electric used?

I am also wondering: If I do decide to put polarity guards into all my older touch tone phones, then what about my special model 2500 touch pulse phone? For some reason, it too seems to be polarity-sensitive, so should I put a polarity guard on it like the touch tone models, and if so, how do I do it?

[McHeath]

This looks like a questions for bwanna, she's got the pulse of the phone company.  It seems like polarity was discussed some time back and if memory serves the general feeling was that it no longer is of much concern to the phone companies, but I may be off there. 

[bwanna]

as a matter of pride in my work, i always in ensure that my pair is in code & tip is tip & ring is ring. there may be guys who don't, since it usually will not cause an issue anymore.

z-dee put a trouble report in if you want, service calls keep us working. if you don't carry an maintenence plan for inside trouble, make sure you are right before you call it in.

or you could just flop the premis wire at the network interface.

[JorgeAmely]

or you could just flop the premis wire at the network interface.

Does that mean exchanging tip and ring? I would do that and save the expense of buying polarity guards.

[paul-f]

The phone companies haven't cared about line polarity for decades.  The features that originally used polarity are long gone.

Complaining is futile.

Others who complained reported that it was difficult to get anyone on the phone in customer service to comprehend the problem, let alone get interested in fixing it.

As has been suggested, your best bets are putting polsrity guards in everything or just swapping tip and ring at the line entry point.  It shouldn't happen too often.

If you want to make the process simpler for the future, you can install a DPDT switch at the entry point, so changing polarity becomes a simple flip of the switch.

[bwanna]

yes, jorge...that is what i meant. easy to do.

[Dan/Panther]

Is there a way to put the polarity guard into the line wiring, and save having to put one in each phone ?
D/P

[Phonesrfun]

No.  They would make it so all ringers in the house would not ring.  

They need to be installed individually in each phone, and in the circuit on the other side of the hookswitch than the ringer.

Good question and idea, however.

[JorgeAmely]

If you put a full wave rectifier on the phone line, when the central office sends you the ringing voltage, your phone will see a DC  level and the ringer won't ring. The ringer wants to see the positive and negative excursions of the ringing voltage to swing the clapper around to hit the gongs.

Non electromechanical ringers will work, in fact, that is how modems detect a ringing signal, by rectifying the line and running the output through a voltage comparator.

In older phones (like the ones we collect), the hook switch, upon lifting the handset, will expose the full wave rectifier to the line and guarantee that the polarity will always be correct. At this point, the rectifier acts like a special switch and only two of the four diodes are in operation. Your voice information (which is an AC signal superimposed on DC) is not rectified.

My 2 cents.

[Phonesrfun]

Jorge:

Your 2 cents was a better story than mine.  More bang for the buck as they say.

[zuperdee]

UPDATE: The problem is worse than I thought--I reversed the green and red connections at the junction box inside my garage, and now the polarity is correct at every jack in the house. HOWEVER, when I tested the polarity of the "To Phone" jack on my old Pacific Bell-branded Caller ID box, I found the polarity on it was reversed! I guess this proves that the phone companies themselves really don't care about correct polarity anymore, and I should just throw in the towel.

I think I will ultimately install polarity guards in all my older phones that need them, because there's obviously no way to ensure consistently correct polarity anymore.

So now: Where's the best place to get polarity guards, insulators for them, and how do I wire one to my touch pulse phone?

I am wondering now just how much the phone companies EVER really cared about polarity, considering the fact that Automatic Electric phones always had polarity guards, and considering that rotary phones are not polarity sensitive. On the other hand, I also find it interesting that my touch pulse 2500 is polarity sensitive, considering that it was designed for lines where non polarity-sensitive phones were supposed to be the norm!

[JorgeAmely]

Daniel:

I had the same problem in my house, but fixed it by reversing the polarity in those jack boxes that needed it corrected.

[bwanna]

daniel, check the back of the jack into which your CID is plugged. wires might be reversed on the lugs there.

being a field tech, i have to defend my craft a little here. i would not say that the phone company does not care about polarity. there are many instances when tip & ring could easily be reversed. working in pulp cable where there is no color code is one. on a section cut in pulp cable the techs are id'ing pairs by tone & splicing to the new cable.in pic cable sometimes a orange wire might be taken for red...or slate for white. in the times when polarity was an issue, these errors would be quickly corrected because they were service affecting. if the error does not cause a service issue, who would ever know?

off the soapbox now....thank you very much for listening

[zuperdee]

I already checked, and the polarity going into the CID is correct, but coming out of it is not, so the CID box itself is obviously reversing the polarity.

[paul-f]

One way to handle polarity reversing modular devices is to make up a polarity reversing cord.  (Crimp one of the modular plugs on "backwards.") and use a F-F adapter to make it a M-F polarity reversing cord.

I found that some of the cheap F-F adapters already reverse the polarity, so I put a strip of black electrical tape around them and use them for polarity reversing.

It's also handy to have a few spares around in case the phone company flips polarity again.