All XLR's are Balanced I/O;
Pin 3 HOT(+ phase)
Pin 2 Cold (- phase)
Pin 1 Ground,

For Unbalanced connections
Inputs: connect pin 2 to pin 1
Outputs: float Pin 2

NOTE: For Mackie 8Buss AUX connection use "BLC" series cables modified by Service for pin 3 hot @ $3.00 ea