Disclaimer: This posting is a work in progress. I’ve mode this some years ago and was asked to provide some documentation:

I have parts of a SAIA PCDII that I wanted to make use out of. The ourput boards have 6 relais each and 8 of them are connected to a backplane connector. This makes 48 mains voltage (low current) switchable channels.
Confusing what I mean? Have a look at this video

I’ve found some of the pictures I took while working on this and just a few days ago I found the box with the hardware itself.

For now the old pictures.

One of the output modules
I desoldered the ICs to work out the schematic
detailed picture of the output board sans ICs
Eight output boards in the extension case


Unfortunately I just this one picture of the pin out.

out of focus and confusing pin out – sorry


Arduino sketch


  • redraw schematic
  • Figure out connector type
  • sketch pinout of PCD2.A220 board
  • sketch pinout backplane
  • comment ino file

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