atcomsystems.ca/forum Forums Other TDM Phone Systems 1A2 and Comkey Telephones & Systems real interesting service call

Here's something I'm still stumped on and need someone to enlighten me and my installers. About a week ago, I had a few jacks terminated at my house after the electrician ran a few new CAT-5 cables in addition to some 23-pair cables for my 1A2 system to be installed someday. (Yeah, I know I could have terminated them myself and saved a bundle, but I didn't have the time and worried I might cut off a wire too short.) Anyway, everything worked fine until last night when I couldn't dial out with my polarity guarded TT phones. And it was the whole house. My thought: the phone co. must have reversed the wires because they all were working, all 17 of them. I asked the installers to come back and modify a jack in our bathroom and reverse the wires. They did at the network interface but the phones still couldn't dial out and showed the polarity was still wrong. I told the installer he must have confused the 2 wires and reverse them again. Same thing again. And wires from phoneco are correct. Well, if switching them outside doesn't work, switch them in the basement. That worked. But how or why?
Wiring goes through DSL filter which is not new and a Viking Ring Booster which was added last week. Any thoughts, guys?

The answer sounded simple until I got down to your last few sentences. I'm stumped as well.

Who's your dial tone provider?

So polarity wouldn't be the issue.

Are you saying that these are phones that have built-in polarity guard circuitry, or are they phones to which you have added the PG?

Maybe the phone co installer was confused. He may have understood you to mean that he needed to reverse the wires on BOTH sides of the NID connections. That would essentially negate any reversals. Did you actually watch him do the reversals, or did he just say he did them, and you believed him? I'm not saying he lied to you, just that he may not have understood what he needed to do.

Then, when you did the reversal yourself in the basement, you fixed the problem.

is it only the phones with the polarity guard that aren't working ?

can a plain old cheapo phone call out ?

have you tried the polarity guarded phone plugged in at the NID ?

if you dont feel competent enough to swap polarity at the NID or take a jack of the wall and swap the wires how do you feel competent to install a polarity guard ?

He said he fixed it already by reversing the wires in the basement.

1. Perhaps I used incorrect terminology with polarity guarded. These are old-style 2500 TT telephones that require correct tip and ring to dial out on.
2. My provider is good ole AT&T Indiana.
3. I did not install a polarity guard so I am sorry if I gave anyone that impression. But it is not a matter of competence with me - it is a matter of time and dealing with wiring that has no "give." It comes out of the wall a fixed length - no slack. That is the way the electrician pulled the wire.
4. I saw the installer physically change the two wires in the NID. Today I went out and confirmed he was working on line 1 as we have 2 lines coming into the NID.
5. Yes, I could dial out on a rotary phone or phone without polarity issues.

6. yes, I used a polarity tester (Radio shack) at the NID and the POTS line was correct polarity. Had no trouble dialing out via NID so problem obviously house wiring.

By definition (and common usage of the language) a phone with a polarity guard "guards" against wrong polarity. There would be no reason to "guard" against correct polarity.

So, older phones, made during the period when the phone company charged extra for DTMF service, did not guard against reversed polarity, for a financial reason. TPC could (and did) reverse line polarity at the MDF when they discovered a subscriber "illegally" using tones to dial out.

Later, when DTMF service became "free" there was no reason to prevent dialing. In addition, with the advent of end-to-end signaling, phones with polarity guards were needed to prevent blocked dialing after call completion that might involve inadvertent polarity reversals.

We're glad you got it straightened out. I would not trust any tester made by RS, though. The best tester is the phone itself. An experienced repairman can pretty much tell wazzup just by listening to the sub's phone.

Is the correct phone parlance perhaps "polarity sensitive"? Thanks for explaining the difference to me about polarity guards and why the phone company had the financial interest to not use them.

Even though everything is working, I still can't understand why switching the two wires at the NID did not affect the polarity inside the house. And I saw the installer physically do it.

I'm tempted to say "chalk it up to MF" and leave it at that. However, what if the NIU L1 is wired to your house's L2? I would have confirmed if L1 went dead in the house when the NIU was disconnected.

Thank you for the unintended amusement these two related comments provided for some of us:

You can perform what is known as "piecing out" on the short leads. That means: take a piece of matching color conductor, and connect it to the short lead, using a Scotchlok® , a B-wire connector, or a soldered and shrink-tubed splice.

Use pieces that are about a foot long, and those then become the ends that are "just longer enough" for the job.

To Dave et. al.: Glad I could provide you with amusement. I am not an installer or claim to be: I am a collector interested in business phone systems of the '50s, '60s, and '70s. My goal is to install a 1A2 system in my home, which is why I subscribe to this tech forum.
My wire strippers are 40 years old and do not even strip 24G wire. My only professional tool is a 66 punchdown tool, also 40+ years old, and I punched down my first 25-pair cable a week ago.
Can anyone tell me what the acronyms, MF and NIU stand for in the above post?
Arthur, thanks for your tip when cutting off a wire too short.

Ummm... looks like I transposed the first one. It was supposed to be FM. Sorry :dance:

So, you’re the guy who’s been punching down on my 66 blocks with a screwdriver? :nono:

Oh yeah just like the alarm guy who told me his pocket flathead was a punchdown tool!

Well, I am not an expert on the NID (which I assume is the same thing as a NIU?) but it looked pretty straightforward to me. He took the W/BL and BL/W wires and switched them twice. One final thought: could the Viking ring booster have some sort of polarity guard, although as I say, it worked just fine for a week?

Well if I understand you're last post, if the installer turned them over twice there still possibly reversed. :shrug:

There's your answer. The telco has "lost" the TT function at the CO. Their problem, not yours.

"He switched them twice." That's what I thought he did. That means he (A) didn't know what he was doing, and (B) didn't know what he was doing.

"5. Yes, I could dial out on a rotary phone or phone without polarity issues."
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If I read this correctly OP says rotary AND DTMF with inherent polarity guard work correctly. That would indicate that the C.O. still has DTMF receivers assigned.

Thanks for your additional comments but here is some more clarification:
1. The CO side of the NID was tested and was the correct polarity and I could dial out.
2. During this episode, one jack with reversed wiring did show correct polarity and I could dial out.
3. Yes, if the wires were reversed twice they would be back to original but remember, they were switched once in the basement.

Put the handset to your ear and punch a few numbers on the pad. If you here the dtmf tones your line is straight. If you get dead air its reversed.

loop start
T - GRND
R - -48vdc

John, that's what I did initially to discover that I had a problem and on all the jacks. The problem is fixed now.
Arthur, I was the one who made him switch the wires twice at the NID because I thought he made a mistake the first time. I watched him do it a second time and still got reversed polarity. Here is a summary:
1. All jacks showing reversed polarity. Must be a Ma Bell problem.
2. Installer switches wires at NID for 1st time. All jacks still showing reversed polarity, CO line correct polarity.
3. I think installer must have accidentally not switched them, so I ordered him to switch them again while I watched him do it. All jacks still showing reversed polarity.
4. Wires switched in basement. All jacks OK.
Bottom line: this seems impossible and why I posted this to the forum.

You said you have two lines. Are you sure he reversed the correct line at the NID?

Yes, I thought of that as well. I can verify which is line 1 and line 2 as I have speed dial on line 1 but not line 2.

There are easier ways to ID telephone lines.

ANA and CID are two of them.

OK, I'll bite. What do ANA and CID stand for?

What does phonenut stand for?

I think Arthur was referring to ANI (automatic number identification) and CID (caller id). They two are not related nor compatible with each other. ANI is only available to WATS (wide area telephone service) subscribers such as toll-free services. ANI identifies the billing number of the calling party. ANI is not blocked by feature codes, and (someone correct me if I'm wrong), it can't be spoofed easily like CID can.

ANA is automatic number anouncement. Most of your carriers use it. When you hear "I see your calling from XXX-XXX-XXXX that's ANA.

Ahh I got it now, thanks for the clarification Bill. So ANA is essentially an automated service that uses ANI to read back your telephone number. Around here I've always seen it labelled ANAC but I suppose that 'C' just means circuit.

ANAC is what you dial into to get the scoop direct from the office switch, most lecs won't give you that number anymore. ANA basically see's the CID and repeats it back to you. If thats not correct I'm sure someone will correct me.

ANA is the announcement that occurs when you dial the code. It can be 958, 9580, or some other set of digits. It is a function of the serving CO.

It has nothing to do with CID. CID is FSK that is sent towards the called party during the silent interval between the first two rings by the completing CO.

The phonenut was trying to identify one of two lines by observing whether or not it had a custom calling feature. With CID, the easiest and quickest way to ID a line, if you don't know the ANA code, is to call your cell phone from the suspect line.

Then I agree with hacky. I call that the ANAC. I thought you were talking about the call announcement almost all LEC's and LD carriers use, which is based on the incoming CID.

EDIT: to add all the 958 CO codes are long gone around here and other areas I've worked in. It's now either an office code other than 958 or a toll free number that needs a password. Some of the milliwatts and quiet terms remain but that's about it.

There's a 1K test tone number that still works out of the CO near my house.

The 958 code still works here in NJ for Verizon CO's. Also the old automatic ringback code works as well (I'm not sure what it is officially called.)

When I was 13 a NJ Bell tech came to my parent's house to repair the static on their line (water in the splice boot.) The guy let me tag along and watch him, and he showed me the automatic ringback number that the techs used. From my parent's exchange you would dial 551 Then you would "flash" the line and hear a steady tone. Once you got the tone you would hang up, and a few seconds later the CO would ring you back. He told me that the exchange code would vary from 550 to 554 depending on the exchange you were calling from. I never found out how or why, but this works for my exchange using 553. Both of these things have proven to be very useful over the years.


Lou

Here in Brooklyn the ringback code was "660 6".


Sam

NOT PUBLIC INFORMATION!

Come on, guys!

These are obsolete codes, for the most part. You can go back and delete the references in my posts, if you want to.

Sorry Ed...didn't mean to offend. I didn't think it was a big deal because these codes are published all over the Internet. If you do a simple Google search you will find them. You will even find international codes.

Lou

I didn't think they were detailed enough to do anyone any good. After a re-read I do see a couple, those I'll edit.

Most folks outside the business wouldn't know what we're even talking about, but Ed's right if they want something like that let them dig for it.

OK let me, or one of the mods know if anyone thinks it needs even more editing.

The OP took it down this path anyway so that's the only reason we didn't direct it back on topic.