ЕС7978.0007 Serial port board
This board based on 2 National Semiconductor's INS8250 ics.
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ЕС7978. Memory Board EC7978.0003-002
EC7978 is a IBM XT compatible PC from late Soviet Union epoch. Few days ago i got set of the electric boards without a case. And here is first one - EC7978.0003-002 memory board with: - 18 TM41256 (256k x 1) - 18 КР565РУ5Г (64k x 1) So total capacity should be 512kb + 128kb = 640 kb