Input signal description, Pin 1 (+22v), Pin 2 (gnd) – Dukane DPC II Plus 9001:2000 User Manual
Page 51: Pin 3 (isolated operate in), Pin 4 (isolated common), Pin 5 (isolated press control), Pin 6 (not used), Pin 7 (gnd), Pin 8 (operate), Pin 9 (isolated auto stop)