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

All the slots are hard wired to specific locations on the punch block. I believe on that KSU slot two is to the right of slot 1. Slot 3 is directly below #1 and slot 4 is to the right of #3. To test, insert a card in a slot and then short the appropriate A&A1 leads. You'll here the card click. Move the card to another location and verify what's what.

On most of the other key systems, the cards started with #1 on the left and went straight across, but there were exceptions.

Grounding is crucial with telephony. So crucial that I didn't even think about it. You install a Telephone system. You ground it. No questions, no ifs, ands or buts. KSUs took a #12, Small PBXs took a #6 and bigger systems took bigger grounds. Much bigger.

But everything was always grounded.

Glad you're having a good time with the project.

Sam

We had a clerk, Suzy, in our field office in New York City during the 1970's who would answer the foreman's line and then transfer the call from a repairman to the appropriate foreman. We would call in when we had a real weird problem, or needed some info from a BSP that we didn't have on the truck.

Suzy had overheard the foremen over the years to the point that even though she didn't know anything about phones, if the foreman was busy, she would always ask "Did you check the ground?" or "Did you check the violet leads?"

If we said "Yes" then she'd be stumped, and let us talk to the boss.

Once again, I have a complete noob question.

I have gotten my KSU and phone to ring on incoming and the light for line one behaves like it should. If I only had one line, this would be perfect.

However, I will have two incoming CO lines, and I have two 400D KTU cards. I realize that I need a three pair cross connect from the keyset to the connector, i.e., I have a three pair from the top six terminals going to the top six terminals of my keyset block. This is for line one.

In order to get line two to the same keyset, I need to take a second three pair cross-connect and connect the same keyset to the second set of six terminals on the main block to the keyset block, right? In other words, each keyset needs one three pair crossconnect for each line?

Thank you all again!

Joe

(P.S. I hope that I did not confuse everyone to death with this one...)

I could be wrong but if I remember right, line 1 requires 3 pairs. The lamp grounds are commoned so it's 2.5 pairs for the other lines.

Someone make sure I am right

I sent you a link for the BSP covering the 2565HK telephone. Do you have it handy to refer to?

YES __________

NO __________

Hi Arthur,

Yes, I sure do!

However, I am not home, and will not be until Sunday night.

I will continue to study the BSP this evening.

Best,

Joe

Hi Arthur,

Thank you! I figured it out from the BSP and was able to answer my own question. I will try better to figure these things out before I ask!

Best,

Joe

The first pick up (PU, or line appearance) on every phone requires 6 wires. T, R, A, A1, LG, L.

All 6 wires in the cross-connection are terminated at both ends.

The A1 lead provides a ground, via the switch hook and NC contacts of the Hold key, for the first and all other A-lead contacts.

For every subsequent PU, all 6 wires are terminated at the KSU block, but at the station end of the cross-connection, the Orange/White lead is whipped around the other 5 leads, and the 5 leads are terminated on the station block. Inside the set, the A1 leads for the other PU keys are insulated and stored.

The above describes a standard 6-button phone. In 10-button phones, (830/2830 type) the spare A1 leads in the set become the A leads for the 6th, 7th, 8th, and 9th PU keys. It's OK if you terminate the A1 leads at the station block, but if you have to go back and upgrade the phone from a 6-button to a 10-button, you would need to disconnect those wires to allow the A leads from the extra PU's to be terminated.

In some telephones, the Lamp Ground leads inside the set are commoned, but the LG from each line card should be terminated to provide adequate lamp-ground return, especially on 10- 20- and 30-button sets, to prevent cross-modulation of the lamps during flash and wink sequences.

In a large system, the LG leads can be omitted when wiring house pairs to a distant closet where a bunch of phones will be terminated. In this case, a separate large ground bus is installed at the closet, and all the A1 and LG leads (and buzzer/ringer return grounds) are attached thereto. In addition, a lamp extender can also be installed with a separate 10 Vac supply in the closet to provide adequate lamp battery.

This method ensures an adequate ground and lamp supply near the phones, and allows the installer to use 2 house pairs per PU, making the job less confusing and more elegant in its symmetry.

In the earlier 1A systems that predated 1A1, the leads were called T, R, B and H. (for Balance and Hold.) Lamp ground and lamp were generally not used.

Installers in the 70's 80's and after, still occasionally referred to the A and A1 leads as the "Balance & Hold" leads.

What happened to T R A and L? The lines 2-9 of a 10 button set were somethimes shortcut wired with just those 4 leads. You guys sure used funny words :-)

That method uses only one 24 gauge wire connected to one mounting cord lead for 9 lamp returns. See my remarks above about cross-modulation.