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Olympia ICR 412 Technology


Second-generation all-SSI ICs.

ICs are from the Fairchild 9930 DTL logic family, made by Philco in the US and date coded from 1969

  • 9093 Dual JK flipflop
  • 9930 Dual 4-input Expandable NAND
  • 9932 Dual 4-input Expandable buffer NAND
  • 9936 Hex Inverter
  • 9946 Quad 2-input NAND
  • 9962 Triple 3-input NAND

Architecture, Memory & Speed

  • 12 digits displayed with Nixie tubes and a sign indicator lamp
    • 24-digit results can be accumulated and displayed.
  • Digit encoding and processing to be determined
  • Delay line memory is contained in the flat box mounted under the keyboard.
  • Master clock and digit/full-number times to be determined


General construction is in keeping with second-generation machines. The case is more elegant with attention to design details but the internal construction is still quite robust. The ICR-412 has a diecast chassis that is separate from the casing and supports the circuit boards and all other components. Most interconnect wiring is handled by a printed circuit backplane and the remaining interconnects are well-made and neatly dressed.

The keyboard uses individual magnetic reed switches.