IBM vacuum tubes

Nigel Johnson nw.johnson at
Mon Jun 22 06:58:21 CDT 2020

An electronic parrot in the vacuum tube days? -- must have been very large!

On 22/06/2020 07:56, William Donzelli via cctalk wrote:
>> Thanks!  What is the secret decoder ring that tells you 188 means GE?
> EIA manufacturer codes. These were often applied to private and house
> branded labelled tubes. Other numbers are 274 for RCA, 280 for
> Raytheon, 158 for DuMont, and so forth.
> EIA codes were used for non-tube electronic parrots.
> --
> Will


Nigel Johnson

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