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#34b Dual Serial Module with Z80 SIO/2 and Crystal Oscillator

Nearly a year after the first version of the SIO/2 module I have finally released the design. The module works fine, but If you are looking for a dual serial module I would recommend Steve Cousins SC104 SIO/2 module, mainly because it is better documented.


  • Z80 SIO/2 dual serial module
  • Crystal Oscillator
  • (rec. 7.3728Mhz = 115200 baud)
  • IO address selectable
  • 51 x 102 mm
  • RC40 bus connector


  • PCB - 34b
  • DIP-40 socket
  • DIP-16 socket
  • DIP-14 socket
  • Z84C4204 or better
  • 74HCT138N
  • 74HCT02N
  • Crystal Oscillator, rec. 7.3728
  • 2.2k resistors (8x)
  • 100nF capacitors (4x)
  • 2x8 pin male connector
  • 6pin angled male adaptor (FTDI) (2x)
  • pins and jumpers
  • 1x40 pin angled male connector

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