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, communication is allowed via the communication conversion device even when the communication systems of the display device and the pulse oximeter are different.
