For normal operation (not using the accessory sockets), jump Pin 1 to Pin 8 and Pin 6 to Pin 7 on both sockets (indicated by the dotted lines in Figure 7; the jumpers are set this way at the factory). To invert the input polarity, that is, to make XLR Pin 2 (+ ) and Pin 3 ( - ), remove the existing jumpers and jump Pin 1 to Pin 7 and Pin 6 to Pin 8.