Note that there is no velocity data sent to the pedal MD-1 board - the pedal division on an organ is "not expressed", meaning that it plays at full volume at all times. The reason is simple - the swell shades that normally control volume on a pipe organ (much like vertical Venetian blinds which either let through the sound or muffle it) do not work well at the low frequencies of pedal stops. Theoretically this might create a problem if a pedal coupler couples to one of the other divisions, but I ignore this since the only voices that even use velocity information are CM32P voices, which will not be used for pedals anyway.
These cables have a DB9M male connector at each
end, and only two wires: output pin 2 of the MD-2 card goes to input pin
3 of the MD-1 card, and pin 5 (ground) on one end goes to pin 5 (ground)
of the other end.