atcomsystems.ca/forum Forums Other TDM Phone Systems 1A2 and Comkey Telephones & Systems PEI 1A2 equipment question

I'm taking a chance that someone here may remember PEI 1A2 and have information to help me connect the phone and a conventional KSU.

I have a PEI key telephone model 5933L1 manf. Nov 1987 with 50 line keys and 40 speed dial numbers. I've figured out the basic T/R A/A1 LG/L connections, but not the other power, control, and signaling that must be on additional pairs, likely on the first of the five 25-pr Amphenol cables. I also have no idea whether any external logic was needed beyond 400 KTU cards. I've found no literature specifically for this phone or its series, and only one incomplete document for a later 1993 "ElectroKey" descendant. PEI couldn't help. I'd appreciate any literature or references, recollections, or (at this point) informed guesses.

I'm not sure whether you'll be able to see this photo:
https://www.dropbox.com/s/kctwwvau8vd5uu3/Front%20.jpg?dl=0

If it starts a trip down memory lane, that may be a sufficient result ...

Thanks.

-- Alan

I think I found the wiring diagram...perhaps, perhaps not.

https://www.telephonecollectors.inf...wiring-diagram-don-t-use-this-one-2/file

Other than that...I'm hitting a dead end.

I worked on Plant Equipment 1A2 back in the sday, but they didn't look like that. Pretty much straight 1A2 only 50, 100 & 200 button units.

Sorry,

Sam

I am just guessing here, but thought I'd give this a go as a suggestion. Back in those days, many manufacturers' 1A2 products were often designed to mimic the styling of Western Electric's Comkey sets. With that said, they didn't have traditional ringers or buzzers. The associated pairs (yellow/slate and yellow/orange, respectively) were used for other purposes on electronic sets. Again, this just a guess, but I'd start with the yellow/orange for power. I'd check for continuity on both of these pairs, plus all of the violet pairs on the first binder. Then, using a 24VDC power source with the lowest Amperage fuse you can get, connect it to the pairs that give you continuity to see if you can at least get power to activate the features. After that, the rest might be easy.

Thanks for the suggestions. I have a bench supply with which I can set voltage and limit current with a pot, so I may take that approach. Rig up a safe breakout box so I can access the pairs reliably. Then hope that PEI was either careful about being consistent with polarities, or careful about protection against reverse polarity. Continuity testing should tell me about diodes.
I suspect there are connections, at a minimum, for common audible (Sonalert), constant power for dialer memory, and constant power for button release solenoids. Now to make space and make time to experiment...