SIO-4D Serial Comms Card
SIO-4D Serial Comms Card


  • Selectable RS232/422/485 serial channels
  • Link selectable serial channels as COM1 to COM8
  • Parallel channels selectable as LPT1/LPT2
  • 1 x 25 way and 1 x 9 way male D type connectors
  • 3 x 16 bit timers
  • Power requirements 5V d.c. at 500mA

The SIO-4d provides the user with four serial communications channels and two parallel printer ports. Each serial channel may be configured to appear as “COM 1” to “COM 8” within the PC port map. Each parrallel port may be set either “LPT1” or “LPT2”, but may not share the same setting. The card supports all of the standard interrupt levels for communications on the IBM PC. Any or all of the serial channels can be link configured to operate to either the RS-232 or RS-485 (balanced line) standard. For RS-485 modes, a link selectable active termination is provided to give line impedance matching for long distances without loading the lines during non-active periods. Base address selection for each serial channel is simplified, requiring just a single link, set to the desired port number for each channel.