The ATB's are designed for use in two hand machine controls. The timing sequence is initiated by depressing one of the two buttons. At that time a .3 second delay is started. During that time the second button must be activated while the first button is maintained to permit the ATB output to be energized. Both buttons must be maintained or pinch point switch closed to allow continued operation of the machine. If either button is released, the ATB output will be interrupted. Both buttons must be released to reset the ATB. With the timed output options, the palm buttons must be maintained during the timed pulse period. To restart in this operation, the palm buttons must be released and operated again.