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#603642 09/06/16 05:33 AM
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ChrisRR Offline OP
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I will start by saying this is mostly a question of curiosity. That being said, maybe I'll learn something I didn't know. I have a pile of line cards, better than 50 I would guess. Some are ITT 400E cards, some are specialty cards like tie lines and manual icom cards, but the majority are 400D of various issues. What I'm curious about is; Does anybody know what changes were made to each issue? Was/is there some document that spelled out all the changes over the years? I know issue 15 allowed for bridged ringing, where all issues prior were grounded ringing. This mattered to me because I have a bunch of VoIP lines, and we all know how that goes. However, on my copper POTS line right from Fairpoint, all the other issue cards work just fine. They ring up, hold, release, and do what line cards do with equal aplomb, at least as far as I can tell. I haven't left them in for extended periods to see if they have issues with phantom ringing or some other wonky trait. I do know that the issue 14 card I have in there now works splendidly considering there is a rotary set on the line before the KSU. The pulse dialing doesn't make it falsely ring up or anything. It seems to just plain work. I guess that was the point, but obviously they had to be changing something to come out with 15+ versions of the 400D card. I'm guessing 15 was the last, since I've never seen a 16. Seems like the stuff Western Electric came out with after the D series just sucked. I refuse to use the G and H cards I have.

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ChrisRR #603650 09/06/16 04:51 PM
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You may find a BSP that will have some major change, but, most of the issue changes were Western Electric modifications for component changes due to manufacturing run changes. For example, a resistor may have been 20% tolerance and the new run is now 10% tolerance. That goes for capacitors and relays as well. Some, and these would have a BSP associated with it, were major changes in reliability and/or feature changes. If the revision affected the installation or operation of the card, and a tech needed to know what the revision was designed to do, then a BSP was issued.

The G and H revs were answers to ITT and others providing MOH function.

Rcaman


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ChrisRR #603662 09/07/16 03:07 AM
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I know that one revision was to allow it to provide music on hold prior to the introduction of the ComKey system around 1975. I'm thinking that the G version came along shortly thereafter to make them more easily-identifiable with the pretty blue handle. The H Version (as I was told by an old-timer from C&P Telephone) was to address the issues with power consumption, relay contact wear and noise. Apparently, customers were complaining about the clicking. I'm not so sure that I believe the noise part since every manufacturer was going solid-state in the early 80s.

The 400G also introduced modular option plugs, rather than punch-down option straps. It was said that after repeated refurbishing of previous 400 versions, the solder joints at the bases of the punch down clips became vulnerable and prone to phantom issues.

Let's also remember that there was a drive by many businesses to simplify everything at the time, and the Bell System was all about efficiency. Their stuff was rented, so making it last longer between service visits meant increased revenue. That makes perfect sense to me. With the 400G, you had only a few choices on how to place the jumper plugs. You really couldn't mess it up. Bell was big on goof-proofing their hardware.

The in-use LED was also handy in large installations. We used to flash a line repeatedly while someone would listen for the clicking card. What a pain. It was much improved when this flashing could be seen in a large rack. I swear that ITT and others didn't come out with this feature (as in ITT's 400E) until long after WE came out with their 400G, as in ten years.


Ed Vaughn, MBSWWYPBX
ChrisRR #603665 09/07/16 04:55 AM
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ChrisRR Offline OP
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Ed, I can't imagine relay contact wear was any kind of a major issue. I mean these cards are still around 40+ years later, many of them never refurbished still happily chugging along. I don't doubt your word, you still actually service this stuff in the field, which gets more use than my hobby stuff. I can't imagine there's ever much current being switched by those relays. The reason I don't like my H cards is they don't reliably go on hold. I forget what the rigamarole was, you had to be off hook for so long and had to hold the hold key a certain length of time, or whatever it was, but I just plain didn't like them. What I am more curious about is the difference between issue numbers on the 400D series cards. Seems like most of the other cards only had a few, but the 400D's had upwards of 15. I'm sure some of it is like Ralph said, a component change or something, but I'm wondering if there was ever a fairly significant change to the way the card worked. I use issue 15 as an example, the change allowed it to work on bridged ringing.

ChrisRR #603701 09/07/16 10:32 PM
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"I swear that ITT and others didn't come out with this feature (as in ITT's 400E) until long after WE came out with their 400G, as in ten years."

Ed -

I'm old, but I'll swear that ITT had LEDs on their 400Es back in the early to mid '70s. I don't remember seeing a WECO 400G till maybe '77.

Of course I have no idea what I ate for breakfast this morning so how I think I can remember things from 40+ years ago is a little ridiculous.

If I have the time I'll go down the dreaded basement and see what I can find.

And yeah, Chris I just (last year? year before?) sent Uncle Arthur a crate of 400D cards for a project he was working on. I think I disconnected them from Noah's ark and they were still working.

Sam


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Silversam #603704 09/08/16 12:29 AM
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Your right, ITT had LEDs on their 400Es. The tiny red LED looked more like an after thought add on, sticking out with the exposed connecting wires. ITT's KTUs were not as durable or solid built as Western's.

ChrisRR #603709 09/08/16 01:23 AM
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SanBar was the first manufacturer whose cards I saw that had busy lamps. Their 4000F's were very reliable cards. Fun Fact: They were made in Mexico, and our (New York company) Union made a futile attempt to boycott them, on the "Buy USA" bandwagon, until reason won out. The reason(s) were that (1) you can't fight Mother when her mind's made up, and (2) they were so much more reliable and easy to use (because of the pilot lamp) that we soon admitted that even though they were made in a non-union 3rd world country, the electrical advantages outweighed the moral disadvantages.


Arthur P. Bloom
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ChrisRR Offline OP
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Originally Posted by [email protected]
ITT's KTUs were not as durable or solid built as Western's.

Maybe so, but they are a heck of a lot easier to fix. I've had two cards go bad on me since I got into 1A2, one was a western, and one an ITT. The ITT card I changed two 1N4004 diodes and it was back in the KSU. The western card... still in the junk drawer. Can't figure out what went bad to save my life. It's been so long since I looked at it, I don't even remember what screwy thing it was doing.

Come to think of it, that bag of 1N4004 diodes has served me well. I bought them to fool around with building a ringing diode matrix and I gave up on that (it worked, just didn't need it), and I've fixed a line card, a guitar amp, an Avaya contact closure, and a bunch of other things with them.

ChrisRR #610845 06/04/17 08:09 PM
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WECo 400D KTU manufacturing changes and issue history are all spelled out in the SD. You can find it in the TCI library. The SD is always the go-to place for this kind of info.


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