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

So in that picture; what is located right beside the power supply on the left side?

It appears to be an 89b bracket and a transformer . If I had to guess ! Which this is only a guess !

I'm back and I heard you guys talking about me. The shadow knows.

On ITT 512 KSU's, there was a small fuse panel mounted to the left of the power supply on the mounting rails. It utilized flat fuses. I don't believe that any other manufacturer did this, except possibly Stromberg-Carlson, so I am pretty sure it's an ITT.

Now as for that thing to the left of the KSU itself, your guess is as good as mine!

It looked like a fuse panel, that supprised me though, the power supply also has flat fuses on it (I have one). ITT must have liked the extra protection?

Nice Avatar Simon! That's an oldie but goodie!

Yes, it is a supplemental fuse panel, but not like what you would think, as in secondary surge protection. It just was used to split out the high-amperage outputs of the power supply into groups of line card slots.

The 512 KSU that ITT made was a variation of a Western Electric 584 panel on a rack with a cover. It wasn't truly a 584 panel though, because 584's had lots of fuses to localize power distribution to the individual cards or groups of cards. While the 512 was still a 13-line KSU, it lacked this individual localized fusing of high-current outputs, like lamp power.

Even with small phone stuff, those 1A2 power supplies threw out a lot of amperage, sometimes 10 amps. A short under a single 10 amp fuse would have certainly caused a risk of fire. I mean, 18 gauge wire is rated to carry that amperage, but when you get down to 26 gauge line cord conductors, it could get ugly.

Those fuses were just there to break the 10 amp output into more managable 2.5 amp circuits. I am sure it was a UL/CSA requirement.

Thanks Ed, I knew you would appreciate it! I have had a renewed interest in the old stuff and I pulled out my old sets including an old 3 slot payphone and started restoring. I did a search for some old logos to install in the dial and found that.

I use to work for a company that did alot of the powered paging speaker systems. We use to find those old power supplies and use them for the speakers. You're right, they are power houses. Before we started fusing individual lines, I had seen twisted pair melted into a single conductor and that 10 amp fuse never blew.

Sorry, guys, been off the board a couple of nights. Yes, Ed called it. If you look "under" the power supply you'll see where the amp cables plugged in to go to the 66 blocks for fan out.
This one had an exterior mounted Tone Commander 1900 series ICM and all ten button sets, including three wall sets.

And, OBTW is so right ---- NO CID>

KLD

A confidencer is a device which screwed onto a g-series handset which supposedly helped prevent your voice from traveling through your office area.

I have loads of 1a2 equipment, touchamatic dialers, 4a speakerphones, if anyone is interested.
mm

Ahh the good ol days, before IP, patches, patches, patches. I think the Confidencer was the secure handset transmitter used to prevent the Russians from listening in on the old 1a2 key stuff. Hey I use to work on the 1a1 w/ the old 207c intercom wipers and cleaning carbon relays all day. 1a2 was high tech, still love that a-lead and man cave stuff. Still have the 10v lamps, #1 troubleshooting tool back then, besides a screw driver.

that's so true. Put a lamp in the lamp lead at the 66 block, short the a-a1 to see if you were good out of the key system, also good when you weren't getting the intercom ring on buzzers, just put a lamp on the buzzer lead, same with testing button and buzzer.. The good ol' days??