Circuit Boards, 3/23

While cleaning out the dirt basement I came across the circuit boards I made to run my large Lionel Train layout in the 1990's. I thought I would photograph them before throwing them in the trash. A lot of work went into these boards controlled from the ISA bus of a computer. Some controlled relays to control track blocks and others detected being pulled to ground with optical isolators. I programed in the C-language using Unix System V. Seems like a lifetime ago and was before Windows. /hugh

    All photos are public domain.
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