There is provided a peripheral device including a multi-pole plug inserted into a jack of a jack device, the jack device including the jack, a conversion unit that converts a physical amount into an electrical signal or converts an electrical signal into a physical amount, a detection unit that detects whether the jack device is a corresponding device capable of handling multiplexed data obtained by multiplexing the electrical signal input and output to and from the conversion unit, a transmission and reception processing unit that transmits or receives the multiplexed data via a predetermined terminal of the multi-pole plug when the jack device is a corresponding device, and a function switching unit that performs assignment of an electrical function of a terminal other than the predetermined terminal of the multi-pole plug.