Telephone Switching > Electro-Mehanical Key Systems (1A1, 1A2 etc)

Oldest 400-type 1A2 linecard?

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Otto Vaughan:
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.

Rick Walsh

I've never seen a 400A or B. That's definitely old.
Does it work?

Rick, we like pictures!

Otto Vaughan:
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

Otto Vaughan:
more pics

Note early option block with wire wickets (and copper sleeves)



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