Impulse pinout information When the back panel connector is viewed from the outside and held upright: Pin 1 - Serial Ground - is at the "4 O'clock" position. Pin 2 - Remote Trigger - is at the "1 O'clock" position. Pin 3 - Serial In (Rx) - is at the "8 O'clock" position. Pin 4 - Serial Out (Tx) - is at the "11 O'clock" position. The mating cable plug is: Turck PSW4M-2/S90