atcomsystems.ca/forum Forums Other TDM Phone Systems 1A2 and Comkey Telephones & Systems multi- to single-line conversion

Hi, Guys,

Let me apologize in advance for asking what I’m sure are basic questions that you’ve answered a hundred times before. I’m used to working on 500 sets so all this wiring is a little daunting!

I have a 2565 HK that I’m trying to connect a 4 conductor modular line cord to so it can be used as a single-line phone. It would be great if the line 1 and hold lamps would light but it’s not necessary. Which terminals should I connect the wires to?

Also, I have a 568 HAA that has the multi-line cable intact. The connector at the end of the cable has two rows of 25 pins. Is there an adapter that would plug into it that terminates in a single-line modular plug? Sorry for the layman’s terms; I don’t know the lingo. Thanks for any advice you can give!

FinLover, welcome to the whacky world of 1A2 key telephones. Get a screwdriver, a flashlight and a magnifying glass.

The 56X- and 256X-series phones are just 500 sets with a jukebox switch built in. The switch, called a key in our language (hence "key telephone") selects which one of up to 5 lines is sent to the talk circuit.

Inside the 2565, under the dial, is a terminal board with 50 or so screw terminals. Look behind line key #1 (the second button from the left, the first button being the HOLD key)

You will see terminals marked "1T" and "1R" Those are the dial tone feed for key number one. Put your dial tone (only two wires necessary, not four) there. If you want the phone to ring on one line, the red and black ringer leads (follow them from the ringer) need to be removed from where they are now (probably on screws marked "RT" and "RR") and put on the same terminals as the dial tone.

The "HaHa" set has the same terminal board. If the 25-pair mounting cord, equipped with a 25-pair amphenol plug, is present, you can either find a short length of 25-pair cable with a female connector, and mate them, or you can use any one of several other schemes to extract the correct pair(s) of wires to accomplish the task. The first line uses pair #1 for dial tone. That is the White/Blue pair in any cord or cable.

You need to get ahold of BSP (Bell System Practice) # 502-541-415. That will explain the whole thing. Feel free to contact me if you need further assistance. I have worked on approximately three billion of these phones over the last 40 years.

By the way, are either of them pink?

Arthur, what exactly is a 568 HAA?

Jeff:

The HAA set originally used by the gummint, was a 2-wire/4-wire set. There is a relay on board that can bypass the phone's network (hybrid coil) and separate the voice signal into a transmit pair and a receive pair, for secure transmission, and better signal quality. There were several schemes that were used to switch the phone from 2- to 4-wire service. One method was to use the A-lead of the particular line to operate the relay. Another scheme used the left swhk plunger to operate the relay. Upon putting the receiver on hook, the plunger was restored, and the relay released until next time.

Later on, the phones were reworked for civvy use, and the relay became an expedient to provide a "switchhook intercom". The left plunger operated the relay, which took the T & R of the network off the line key, and put it on a manual or dial intercom T & R coming in on a spare mounting cord pair. The relay required local -24Vdc on the Br/Y lead for operation. The red HOLD key was used as a ICM busy lamp. It was an expedient used between the time that the Call Director was being phased out, and until the 83X- and 283X-series 9-line & HOLD sets became available. They used all 50 conductors to provide 9-lines, while a Call Director needed a much larger cable.

Probably too much information, right? I should write a book.

Multi Line Phones were designed to be used with external control equipment called KSUs (Key Service Units). They contained the equipment to provide lamps, hold and ringing.

Having said that, you could jury rig your phones to provide Dial Tone, Ringing and maybe even lamps. No Hold without external equipment.

On your 4 conductor modular cord to the 2565 HK set: Put the green from the cord to 1T and the red to 1R. To get the bell to ring, take the Black and Red Ringer leads off of the RR & RT terminals and connect them to 1R & 1T with the Green & Red leads.

To get your lamp leads to work, you will need an external power supply that provides no more than 10 volts. (A WE plug in transformer part # 2012A will work).

Run the lamp power in on the Black & Yellow leads put one side to the LG (Lamp ground lead) of the lamp(s) that you wish to light. Put the other side on the 1B terminal. Then take the 1H terminal and jump it to the 1L terminal. When you go off hook with Line 1 depressed your lamp(s) will light. I'm sure there's a more elegant solution, but that's the one that comes to mind quickly.

There are a number of adapters that would do what you like with most key sets. One of them is the TRW Cinch Super Mod VI (PN 299-24-00-049) It has a male and female amphenol and 6 @ 4 pair jacks that bring out the first 24 of the 25 pairs. To connect the first line, Connect a standard modular cord to Jack #1 (It will plug in to the 4 pair jack and work).

For lights and bells you will have to wire it similarly to the previous example.

I don't know if TRW still sells this - you could try on eBay, or someone here might have one they might want to sell(I might have one someplace).


Let us know if you have any questions.

Sam

<Edited to correct a typo>

I think I know the phone you are talking about. I remember a site that had all of the different 500 series phones with pictures. Can't find it now though.

Thanks for your help, Mr. Bloom and Silversam! Like I mentioned, I refurbish W.E. 500s and 554s and one of my customers sent me a Moss Green 2565 she found in a junk shop that she wants to use in her home. Thanks to you I'll be able to make it functional.

The rotary dial 568 is my personal phone. It is gorgeous bright red including the cord. I do have a pink '57 500 "soft plastic" set that is one of my favorites. That's a fabulous collection you have there, Arthur!! I'm Moss Green with envy!

Here's the site:
https://mysite.verizon.net/paul-f/we500typ.htm
PS: Moss Green, like my name

Jeff,
Thanks for the link. Interesting although some futuristic models fall into "plug ugly awful" or "what were they thinking". Thank goodness none made it to the market else they might have joined ranks with the Edsel!

Sam