Servos operate by using pulse modulation where the high pulse width determines both direction of servo operation and possibly the speed of operation. The time between pulses is generally 20 milliseconds and is not adjustable by this command. The pulse width generally varies around a mid-point of 1.5 milliseconds (1500 microseconds). Pulse widths less than 1.5 milliseconds cause servo operation in one direction, while pulse widths greater than 1.5 milliseconds cause operation in the opposite direction.

The CALIBRATE command for SERVO allows programmable changes to the minimum and maximum pulse widths. Parameters are pulse width times in microseconds.

Current defaults are minimum 600 and maximum 2400 microseconds.