Matrix Orbital LK204-24-USB - Manual (Page 14)

Figure 8: Fan Header
2.2.1 Advanced General Purpose Outputs & GPO’s 1 to 4
These outputs are capable of controlling high current draw devices, saving power up state, being switched
to PWM mode, and repeat back RPM via Hall effect sensor.
Figure 9: GPOs 1 to 4
Matrix Orbital LK204-24-USB 10