"The phone is a remarkably complex, simple device,
and very rarely ever needs repairs, once you fix them." - Dan/Panther

Main Menu

daisey chaining and unmarked terminals.

Started by Babybearjs, March 16, 2020, 04:15:56 AM

Previous topic - Next topic


I don't know what it is about engineers, but it makes me mad when I discover common terminals and daisey chaining terminals on the old 200 series KTU's that ARE NOT on the schematics... why engineers do this is beyond me... I discovered that terminals 37 and 39, 38 and 40 on the 208 KTU are common and are for daisey chaining the rest of the sets together... (37, 39= Batt B and 38, 40=BG) yet 38 and 39 are the only terminals marked for the battery feed... I don't know why they did this... knowing how the units were originally wired... some of these old BSP's are so poorly done... has anyone else run across this issue? did the techs know about the unmarked terminals? I found similar issues on my 211.... and then they have terminals marked that don't even do anything.... like Terminals 7B and 16B on the 207C... they are there, yet they are not used.... and no explaination to their function or use... if you still work with the old 1A1 systems, share your experiences. it would be fun to hear about other guys experiences with these units and unmarked terminals...


I cannot comment much on your situation, but I can say
I have been A tech for over 45 years, and have encountered your issues many times.
What I do know, is these things have been happening all along.
I believe, and am no authority on it, but when the designers begin a project,
there are many avenues to address.
The hardware side, the schematic rendering side, and the sales side are all done by different people.
And yes, mistakes do happen.
A lot of what you are seeing, has to do with options...
Even tho your system may only use 3 plug able boards, the back plane has to accommodate multiple configurations.
And, when you look at the product and the paper work, these are translations needing to be done, and the workers
SELDOM have ALL the information available to them.


Yea, it's frustrating, but it also helps a lot to have up to date, in your case out of date schematics..
With out current for what your working with/ on it is extreemly difficult.
As for chaining 208s I have not worked on that stuff hardly at all. The only time I even used those was on my first 501 with a 207, and associated KTUs. Then shortly after found the Valcom RT intercom that I still use.
I'm more into 1A2 not 1A1, to me it's easier to do stuff with versus a zillion wires everywhere.

And for setting up special stuff, I use my key phones extra contacts and relays to operate extras.
I do that next to the KSU, all clearly marked wires with chematics I do to remind me of what I have done.
Because there are this occasions that I draw a blank or I'd thought I did it this way, but it was actually that way.

Jack Ryan

Quote from: Babybearjs on March 16, 2020, 04:15:56 AM
I don't know what it is about engineers, but it makes me mad when I discover [...] ... why engineers do this is beyond me... [...] ... I don't know why they did this... [...] ... some of these old BSP's are so poorly done...

I suppose people could look at what Adolf Hitler did and say "I don't know what it is about white-men..." but at least in that case they would know that it was, in fact, Hitler that did those things.



yeh... I hear you all... the 1A1 was discontinued back in the 60's and by the 70's the 1A2 were everywhere... at least those were on PC cards, so it was just a matter of switching out the part... the wiring stayed the same, except for cross connects which are easily fixed... and I also see with the old stuff, the inconsistancy in design... for instance, the power on a 212 and a 207 is mainly on the 9th an 10th terminals (9, 10   19, 20  29, 30  39, 40... ) but with some of the other units they are marked 38, 40, or something like that... yet the terminals are jumped... kind of crazy people even back then didn't communicate good to keep everything even... oh well, thats man for you!   


John, I know this post is a bit old, but if you go to YouTube, and search sxsphil he shows work on his 1A and 1A1 system. He talks about daisy chaining etc.
It may be worth a look for you.


yeah, I know Phil, and he's helped a lot with the issue.. thanks...


Just thought that might help.
Have you talked with him about your ring up problem to get his input?


no, can't get him to respond, he's too busy... still works for Centurylink there in Corvallis, OR., or was last I'm aware of...