I thought I had one or two of these boards but could not find any in my box of STEbus boards. They may be elsewhere but I can't find them right now. :-(

I did have a bare PCB of the version 2 issue 2 board, with the PCB legend modified as requested by RS Components.

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If I don't have a complete board it means I don't have the PAL equations either. However, this is a fairly simple board so I doubt it would be hard to create PAL equations for it.