atcomsystems.ca/forum Forums Other TDM Phone Systems 1A2 and Comkey Telephones & Systems 118A Ring Generator with 551A KSU; Are the two compatible?

Hello all. After setting aside my 1A2 project for a few months I've started working on it again. Today, I'm trying to figure out how to integrate a 118A frequency generator into my 551A shoebox KSU. I have the ring generator temporarily zip tied to the Interrupter.



I connected the ring generator to RG/RB on the 66B5 block inside the 551A KSU.



Upon consulting Practice Section 518-215-407 , clause 2.03(c), 3rd bullet point under Replaceable (Optional) Components, I note that 551A KSU is conspicuous by its absence in the following clause: Moreover, Fig. 10 states, in the bottom right hand corner QUESTION: Can a ring generator be used with my 551A KSU for common audible? If yes, any thoughts or comments to move me in the right direction?

I'm no phone man; just a hobbyist who happened to take an electronics class in 8th grade which isn't much of a foundation. Worse, I'm a hobbyist who has yet to master wire fishing in the walls of my house (but that's a mess for another post). But, this leisure time project is fun to me and your advise throughout this board has made my hobby possible.

Here's one last photo showing my 1A2 project in process:


Thanks in advance,

Mark

PS: Please type slowly as I'm not a fast reader.

Hi Mark,

I am certain that you can use your ring generator with your KSU. You have the exact KSU and ring generator that I do, and your ring generator is hooked up at the same place that mine is. The only difference is you mounted yours on the interrupter, and I fabricated a metal bracket for mine to mount on the back board (The bracket is simply a 45 cent metal bracket sold in a home improvement store... ask someone (if you can find them) for a 'hurricane rated stud bracket'.

Of course, if Arthur or Ed disagree with me, by all means, listen to them. They are both my 1A2 gurus, and they have more knowledge about this subject in their little fingers than I and my cats will ever hope to ever possess in all nine of our lives.

The one thing I notice on your set up is it looks like the plug/socket thing on your ring generator power cord is different than on my 118A.

Look in past 1A2 threads, and you will find pictures of my setup.

Best,

Joe

I really like those red and green wall sets! Where did you get them?

I mounted my interrupter using small metal d-rings screwed to the back of the interrupter.

Mark, at the time that your 551A was manufactured, it was intended to be used with a separate 101A wall-mounted ring generator. The 118A came out much later and a bracket was designed to use it in the 551B and C versions. These brackets had completely different designs. Both were made of "unobtanium" then and certainly are now. Cable ties to secure it to the interrupter were generally the normal installation procedure.

Jeff: Mark's KSU is the 'A' version that had a Hubbell Twistlok Midget connection between the power cord from the power supply and the appropriate extension selected for the installation. As you can imagine, it became very costly to maintain these custom cords, so with the 'B' version, it came with a standard NEMA 5-15 cord connection. The piggy-back cord on the ring generator was designed to simply fit in-line with the original power supply connection.

What Ed said.

Thanks for the info Ed, mine has a standard 'Edison' plug. It is the 551B I believe (not going to the basement now)

Believe it or not, the BSP for Canada also provided for hard-wired power connections to KSUs. I only remember references to versions of the 550/551 having such an option.

I can say with complete certainty that I never saw anything like this, but apparently there was such a requirement. My guess is that this was yet another of those crazy Canadian things that is no longer required on any system.

Thank you, gentlemen. You comments are helpful; it's good to know I may use a 118A ring generator with my KSU.

OK: I have the ring generator connected to the right place on the within the KSU, I have the yellow/slate pair connected to the same row on the 66 block. Common audible should now be functional on all CO lines, at all connected stations? In making test calls, incoming call lights flash and voice is fine upon going off hook but nothing rings unless I wire one station as a line ringer. I tested the 118A by connecting it to the Y/S pair on one station. The ringer activated, so I know the little black box works at least. Any thoughts as to what I'm missing here? I'll review the practice again but any advice would be appreciated.

Some help with the bigger picture would be great too: how does the KSU know to activate the common audible when there is an incoming call on one of the CO lines? Where are CO lines connected into the common audible system? Is there some sort of relay built into the KSU or KTU's? Do I need to make a connection somewhere considering all else (lights and voice) works as it should?

Thanks,

The yellow/slate pair from the ringer should be connected to a B1 and R1 pair. The CA terminals should be looped together with a single piece of wire. Each CA terminal from top to bottom represents the ringing output from each line card in numerical order. Envision them being 'CA1' through 'CA4'. They are factory-wired to each of the R terminal rows. The B terminal rows are factory-wired to the RG terminal where you connected your ring generator.

. . .and then there was the sound of ringing in my house!

Thanks everyone for your help. Thanks, Ed for the for those few sentences above that made the figure/schematic in the Bell System Practice suddenly make sense to me. I was blind but now I see.


Looking at my list, next is making this crappy little MagicJack I bought at Walgreens work as a 3rd CO line. I stuck a tester in it and got a red light -- what's with the reversed polarity? Odd, but can't I just reverse T/R at the KSU where the CO line connects? I've already figured out that the MagicJack thing doesn't play nice with 400G cards but the 400H seems to like it just fine. Loop current is thin; could that be what makes 400G finicky? That's as far as I've gotten. No idea yet what ring voltage will be like but with common audible up and running, hopefully that won't be an issue. I saw a thread from several months ago about MagicJack; will review but I may have many questions in future about this and other fun 1A2 stuff.


You guys are the best. Thanks again.

Kind regards,