To provide a transmission system capable of ensuring reliability of signal transmission. The transmission system includes: a remote unit alternately outputting pulse voltage with a positive polarity and pulse voltage with a negative polarity as a signal by causing a first switching element and a second switching element to alternately open and close; and a master unit accepting input of a signal from the remote unit via a cable, and separating the signal into a first signal corresponding to the pulse voltage with the positive polarity and a second signal corresponding to the pulse voltage with the negative polarity.