In a balanced system the data contained in a series of pulses is input to the driver. The driver reproduces these pulses both in positive and negative form, and sends the positive data pulses down one conductor and the corresponding negative data pulses down the other conductor. If noise is picked up by the conductors, it is picked up equally by both. The receiver inverts the pulses from one of the conductors and algebraically adds them with the pulses from the other channel. The pulses are now at the same polarity and add up. The noise spikes, on the other hand, are now of opposite polarity and subtract, resulting in the noise being cancelled out with no error occurring. This noise cancellation is referred to as common mode rejection.