I recently came across a Western Electric 1A2 line card with component dates of IV-63. 1963 is very early for 1A2 equipment.
It has a sticker on top of a sticker that IDs it as a 400B line card but I suspect under the top sticker the original sticker says 400A.
I know the difference between the 400A and 400B is the addition of a diode. I will investigate to see if that diode was added.
Does anyone have a 400A card? Or something earlier than "IV-63"?
Any interest in a photograph? The option block appears unique too.
I've never seen a 400A or B. That's definitely old.
Does it work?
Rick, we like pictures!
Yes the card works
Believe it started life as a 400A and was upgraded to 400B (diode added). I have a 1965 400B that has "400B" in the traces on the underside; the 1963 card does not.
Here are pics
Note early option block with wire wickets (and copper sleeves)
So I now realize this one actually does say "400B" in solder on the underside Right above "R 7/76" (refurbished) in the last photo. It was so over soldered it didn't loo like lettering initially. So I am still wondering what is underneath the 400B sticker. Seems odd they would but "400B" on top of "400B"!
Perhaps a different version? Or the addition of the diode changed it to a B.
I've seen metal frame cards before but it's been a very long time.
Does it need a system ground to Ring up during an incoming cycle, or will it ring up in either case.
I remember the D cards prior to version 15 required a system ground to Ring up.
And the option block is on the card end, not the head as they were later.
Did they have a C card as well, and E.
I can't find anything on this old of a card, in my BSPs.
I've heard of E cards but I guess they are very rare to find. But I've not heard of C s so I don't know if there was such.
But that's a very cool piece of key system history you have.