A disconnection detecting device includes a confirmation signal outputting module configured to cause a transmission sound signal to be outputted from a signal processing unit, and a detector. The transmission sound signal includes a confirmation signal having a frequency that differs from a frequency band for use in communicating information contained in the transmission sound signal that is sent from the signal processing unit to a communication unit. The detector is configured to detect whether or not a disconnection is occurring in connection wires based on the transmission sound signal including the confirmation signal that is returned from the communication unit to the signal processing unit via the connection wires.
展开▼
