A signal conversion system comprises measuring units, a switcher, a converter, and a host. The converter mutually converts signals transmitted in compliance with a first protocol for communicating with a pre-specified party and signals transmitted in compliance with a second protocol different from the first protocol. The host specifies a given measuring unit among the measuring units communicating in compliance with the first protocol. Then, the switcher switches the transmission channel of signals transmitted in compliance with the first protocol to the transmission channel connecting the measuring unit specified by the host and the converter.