If switch 4 is in the UP position, the Sabertooth 2x25 is in
Mixed mode. This mode is designed for easy steering of
differential-drive vehicles. The analog signal fed into S1
controls the forward/back motion of the vehicle, and the
analog signal fed into S2 controls the turning motion of the
vehicle. If Switch 4 is in the DOWN position, the
Sabertooth 2x25 is in Independent mode. In Independent mode, the signal fed to S1 directly
controls Motor 1 (outputs M1A and M1B) and the signal fed to S2 controls Motor 2.