The ATS system widely used by JR companies has essentially a problem caused by the intermittent transmission from the ground equipment. As a signal information can not be transmitted except at fixed positions, the timing of the changes in signal information may not be detected until the train passes the next transmission point. This may cause missing of the red aspect of departure signal. The continuously-controlled ATS that uses loop cables or AF frequency adopted by some private railways is too expensive in view of the role of ATS that is one of backup systems. In this paper, we propose a method to transmit signal information, by switching momentarily off the track circuit current, called "Slit-Codes", which realizes continuously-controlled ATS with lower consts. In field tests, applicability of this method has been confirmed.