Pulse output only, or by logically

Pulse output only, or by logically relating the reference pulse to the A and B data channels.
Thus pulse it is most frequently used in positioning and motion control applications as an electronic starting point of known position from which counting or position tracking begins.
In long travel or multiple turns of the encoder, the reference pulse is sometimes
used by the control to initiate an electronic check on the total count received from
the encoder. For example, each time a reference pulse is received by the control, the
total count received from channels A and B should be an even multiple of the
encoder's pulses per revolution.