A pulse oximetry system includes: a pulse oximeter that creates biological information data a communication conversion device that receives the biological information data from the pulse oximeter and converts the communication system of the biological data into a communication system fitted to a display device and the display device that receives the biological information data from the communication conversion device. A storage unit of the communication conversion device stores a plurality of candidate communication systems. A user can select a communication system fitted to the display device from the candidate communication systems, and set the selected communication system as a communication system after conversion. Accordingly, in case of presence of a communication system fitted to the communication system of the display device in the plurality of candidate communication systems, communication is allowed via the communication conversion device even when the communication systems of the display device and the pulse oximeter are different.
