atcomsystems.ca/forum Forums Other TDM Phone Systems 1A2 and Comkey Telephones & Systems Polarity issue

Hi! It's me again. I'm doing a great deal of work for this client that has the ITT 1A2 Key system. There are a few issues that, over time, I will post if I can't sort them out myself.

This problem I stumbled upon. The tip/ring polarity is correct from the demarc to the KSU. Leaving the KSU it's also correct. On the first 66 block it's reversed, but the color codes are correct. I thought that there might be something in between the KSU and the block, but I haven't found it yet, It's the only thing that could be the answer to me. Any ideas?

Thanks

The older keypads are polarity sensitive.

If you can't dial out, then reverse the W/BL/ BL/W in the set. There may be another cross connect point in a can in the ceiling that you can't find.

Take the set apart and reverse the line inside the set terminals.

If everything is just punched down (no amp plugs) there has to be something between the KSU and the 1st 66 block. How are determining it's correct at the block on the KSU?

The 66 blocks are fed from the KSU via two amp connectors. I'll have to wait until after business hours, but my guess is I have a cross in one of those connectors.

Dave:

Sorry for the late chime-in. You mentioned polarity issues, but not specifically what they are. Is this a case of just that particular line not being able to dial out or all of the lines on just one particular set?

If the issue applies to all sets that share that line, just reverse the polarity as it enters the KSU, test and be done with it. Granted, this is not a true fix, but it will solve the problem instead of spending hours chasing gremlins.

If it's station-specific, then everyone here who has replied is on the same bandwagon. Something is hidden and will need to be found. Reversing polarity on a per-line basis can be done within some 6-button sets by butchering the terminal strips on the line cord pairs, but it's nearly-impossible on 10/20/30 button ones.

On a side note: What is the exact model of KSU we are talking about? I don't immediately recall any that have two 25 pair connectors for output except San/Bar's pre-packaged units.

I'm sorry Ed. The tip/ring is reversed at the 66 block following the KSU. The color codes are correct, but the polarity doesn't follow the color code. The business is closed now, so I can do some peeking into the amps.

Thanks

No need to apologize. Just attempting to gather nuggets of info to help you put this to rest.

Ed, it probably wasn't kosher, but I used to bring 25 pair out from KSU configured/punched down in KSU, so I could plug it into 1 of those 10 station mutiples that had everything but CO and IC audible multipled straight thru. Of course, when the customer added something like a 10 button speakerphone (You know, the kind that had seven line buttons and the other 3 buttons were for controlling the speakerphone), the whole mess got MESSY, or if enough non-square happened, down came the multiple and up went the X-connect field. But it could sure make for a quick 1A2 install! John C.

John, that is exactly why I asked the question. San/Bar's packaged units did much of what you were doing; They even offered custom Comdial 3564 sets (note the "3" instead of "2"). These sets included a rotary switch in the bottom of the set to permit dial code selection by using a small screwdriver.

These systems were sold at a local chain of "phone stores" in the 1980's on a cash and carry basis. These stores sold optional connectorized 25 pair cables and bridging adapters as needed. There were even some special bridging adapters (CPC) made by Ortronics that included these rotary switches so that non- "3" series sets could still be used.

A brilliant concept at the time, but too complicated for the "I can do that myself" type.

Ya know, I think I remember seeing those at a GRAYBAR 'look and eat' in KC back in the mid 80's. My company was smart enough to avoid the system. We were spread across too many brands/systems already! And I was on a 'consolidate and eliminate' drive! You cannot be everything to everybody and stay in business. All your operating $$$$ gets tied up in spares! You just gotta walk away sometimes. Even suggest a competitor, IF he's legitimate!

John C.