The present invention includes a telegraph controller and an FSK modulator that serve as a signal transmission unit that creates a checking telegraph that is different from a controlling telegraph and transmits the checking telegraph to a pickup coil, an FSK demodulator and a telegraph controller that serve as a signal reception unit that restores telegraph information from the checking telegraph received via the pickup coil, and a communication controller that compares transmission telegraph information included in a checking telegraph transmitted from the signal transmission unit with reception telegraph information restored from a received checking telegraph that includes the transmission telegraph information to verify a telegraph reception function on an on-board side.