Abstract: A communication device for an electronic musical instrument, comprising: an antenna for transmitting and receiving a radio signal of MIDI data and receiving a radio signal of audio data; a radio communication module for mutually converting the MIDI data and the radio signal of MIDI data and converting the radio signal of audio data into the audio data; a control device for mutually converting the MIDI data and a signal for a certain interface and converting the audio data into the signal for the certain interface; and a connector for transmitting and receiving the MIDI data as the signal for the certain interface to and from the electronic musical instrument and transmitting the audio data as the signal for the certain interface to the electronic musical instrument.

Abstract: A merchandise sales system that simplifies the purchase action of the customer is provided. This merchandise sales system constructs a merchandise sales system provided with: a portable terminal capable of reading a two-dimensional code; a member information management server that manages preregistered information related to a member; an authentication server that converts information related to billing referred to when a commodity is purchased (billing information) into a two-dimensional code; and a display device that displays the two-dimensional code.