atcomsystems.ca/forum
Posted By: morephones Possible polarity issue - 04/26/19 08:37 PM
Hi guys,

I might have a polarity issue in my 2565 phone as it will not break dial tone. I was going to see if I could switch tip and ring for each line but the terminals are connected to the board of the phone so I would have to cut the wires. Any way to fix the polarity issue on the network card?

I would fix it at the KSU but I do not think I have enough wire left to do that.

Thanks Brian




Posted By: justbill Re: Possible polarity issue - 04/26/19 08:41 PM
reverse tip and ring on your feed into the ksu
Posted By: Professor Shadow Re: Possible polarity issue - 04/26/19 08:56 PM
Originally Posted by justbill
reverse tip and ring on your feed into the ksu
Or easier still at the NIU.
Posted By: ChrisRR Re: Possible polarity issue - 04/26/19 11:23 PM
If you are only having problems with only this one phone and all the lines are reversed, swap the wires coming from the hook switch that connect to "C" and "F" on the network in the phone. At least if I'm reading the BSP right it should be those two....The BSP I'm reading shows them as blue and white, but I know I've seen one of them being green before.... Anyways, it's the tip and ring coming from the keyswitches through the hook switch and into the network. That will reverse the polarity for all the lines in the phone.

I'd post a picture of the BSP but I'd need Dean to help me out again.
Posted By: Professor Shadow Re: Possible polarity issue - 04/26/19 11:41 PM
Here is the BSP if you need it...easier posting the link than a bunch of images.

BPS 502-543-406

and the LK model
Posted By: Touch Tone Tommy Re: Possible polarity issue - 04/27/19 12:41 AM
Install a Polarity Guard
http://wedophones.com/TheBellSystem/pdf/bsp/2500/502-543-405-8012.pdf
http://www.ridethemindway.com/phone...00-001_to_999-999-999/501-321-100_I7.pdf
Posted By: morephones Re: Possible polarity issue - 05/02/19 03:38 PM
Thanks guys,


Thanks for the help and thanks for the BSP's will work on the phone this weekend.

Thanks Brian
Posted By: Arthur P. Bloom Re: Possible polarity issue - 05/03/19 01:43 AM
There are lots of reasons that a phone can't break dial tone.

First, we need to know more information and what "version" of CBDT you are reporting:

1. I hear tones, they sound correct, but CBDT
2. I hear tones, they don't seem to sound right.
3. I hear wavering tones as I push the buttons
4. I hear a "tink" sound when I push the buttons
5. I hear a click when I push the buttons

additionally...

6 all the lines on the one phone CBDT
7 some of the lines work, but some CBDT
8 I have more than one 2565 and this one CBDT but the other(s) work OK
9 the phone is / is not a WE phone
10 I have checked the polarity, voltage and current of the line(s) in question
11 I have connected a butt set directly to the line(s) at the
a. NID
b. KSU input T&R
c. KSU output T&R
d. T&R terminals on the key in the telephone
...and here are the results of these tests:


So, as the members above have suggested, before you start moving wires around inside a factory-wired, unmolested phone...

(and what do you mean by "...the terminals are connected to the board of the phone so I would have to cut the wires." ? The mounting cord conductors in a typical 2565 are terminated with spade lugs, which are fastened under the screw heads on the key,)...

I would suggest that you do your diagnosis in a scientific and methodical manner.

But tell us the answers to the above sequence of observations. The answer might be as simple as a dirty contact on the common switch of the dial. I have been repairing 2565 sets for 52 years, so I'm confident that I can help you.

JUSTBILL's suggestion is the least invasive and would be my first choice, if I didn't have a butt set (or a 2500 set with test leads) handy. Installing a polarity guard is not a repair. It is a work-around that is not necessary if you follow the logical trouble-shooting scheme explained above.
Posted By: morephones Re: Possible polarity issue - 05/03/19 11:51 PM
Hi Arthur,

Thanks for the help.... To answer your questions.

I hear tones, they sound correct, but CBDT and this only happens on the 4 lines, intercom line work fine.

This phone is a WECO 2564 and I have swapped phones and other phones work fine.

Will check the voltage and current this weekend.

I don't have a butt set but I did rig up a regular phone and tested the lines at the KSU and it work just fine.

The spade lugs are attached to the connector board, I have attached a photo.

[Linked Image]


Thanks Brian
Posted By: Touch Tone Tommy Re: Possible polarity issue - 05/04/19 12:52 AM
They took the 6 wires for a pickup key, and instead of a single spade tip for each wire, they made a piece of plastic with 6 spade tips molded in. This made it faster and easier for the factory worker to assemble the phone, as they just put these strips under the bank of screws and tightened them all down.

You could loosen all of the screws for that bank, take them all off, snip the plastic between the 1st and 2nd, and the 2nd and 3rd, then put them back down swapping the position of the 1st and 2nd, now free, spade tips, but PLEASE DON'T DO THAT

Do you have a volt meter? Check the polarity of the non-working line vs. the working lines.

It is highly likely that you have Tip and Ring reversed at the block for all 4 lines but not for the Intercom, and the other phones you have tested have polarity guards either built into the touch tone pads or installed as an adjunct.

We never used them to correct for sloppy wiring, we used them for GTE central offices that reversed polarity of Tip and Ring when supervising, which ended up not letting you generate DTMF once your call connected. This was in the hey-day of MCI and Sprint, where you had a slew of local access numbers, and had to input your account code and destination telephone number after the access number answered.
Posted By: ChrisRR Re: Possible polarity issue - 05/04/19 01:03 AM
And that is why I made the suggestion of flipping tip and ring where they are connected to the network.

It's entirely possible that the contacts are dirty on the back of the dial. I've had to clean more than a few to get them working.

I knew the spades were going to be attached to those plastic strips, which is why I thought of flipping t&r at the network if it's only this phone. Maybe someone flipped them before, who knows. These things are all pushing 40+ years old. There's no telling who's been in there poking around. My advice is get the BSP, make sure everything is wired as it should be, if not, correct it, then move on to cleaning the dial contacts. No sense in beating your head against a wall if someone has changed a bunch of wires around. Make sure it's wired like it just left the factory, then start the real troubleshooting.
Posted By: ChrisRR Re: Possible polarity issue - 05/04/19 01:14 AM
Originally Posted by Touch Tone Tommy
It is highly likely that you have Tip and Ring reversed at the block for all 4 lines but not for the Intercom, and the other phones you have tested have polarity guards either built into the touch tone pads or installed as an adjunct.


Given that you can't easily swap those wires around..... The fix isn't to start cutting them off the strips and rearranging them.

Using a voltmeter, put the black probe on the white wire with the blue tracer, and the red probe on the blue wire with the white tracer. If the polarity is correct you should see a negative voltage somewhere around -48 volts DC. If you have a positive voltage, they're backwards at the block.

I don't know what your source of dial tone is, but if they are real phone lines or at least decent ATA's, you should get around -48 volts on hook voltage. Most add on intercoms only supply -24 volts but it works just fine. Check each line pair the same way. Each column of terminal screws is laid out the same way. The top two screws are tip and ring for each line. Tip is closest to the back of the phone. (Someone correct me if I'm coming down with CRS syndrome)
Posted By: Arthur P. Bloom Re: Possible polarity issue - 05/05/19 02:40 PM
When you said that the conductors are connected to a "board" I assumed you meant the terminal area of the key. Now I see that you meant the wafers that allow the assembly process to go more quickly.

"I hear tones, they sound correct, but CBDT and this only happens on the 4 lines, intercom line work fine."

So, the dial generates the correct tones, and the intercom operates correctly. In the old days, the DTMF receivers in a CO were much more forgiving to frequency variations than the cheap(er) receivers in a local intercom. Nowadays, I'm not sure about the ATA's.

You hear tones when on a CO line, but you CBDT. The next thing to do is to put two sets on the same cable, press the same CO key on both, press the same TT button on both, and listen for a "beat." The suspect dial may be just a little off frequency. The adjusting slugs on the back of the dial can fix that.

Other than that, I guess 52 years of experience is not enough. I'm stumped.
Posted By: morephones Re: Possible polarity issue - 05/09/19 03:22 PM
Thanks for the help guys.

I tried flipping the tip and ring on the network with no luck. So I had a idea of making a cross over cable for each line to reverse the tip and ring and it worked!!!!! The good part that the reversal of the tip and ring did not effect the other phones on the system.

© Sundance Phone System Forums - VOIP & Cloud Phone Help