Communication device for electronic musical instrument, electric power switching method thereof and electronic musical instrument

An electric power switching method for a communication device for an electronic musical instrument for transmitting and receiving, using a MIDI signal form, various kinds of electronic information in the electronic musical instrument between the electronic musical instrument and an other electronic instrument,

• wherein the communication device for the electronic musical instrument comprises an input terminal, an output terminal, and a battery, and
• the method comprises:
• connecting the input terminal and the output terminal to the electronic musical instrument;
• switching electric power to be supplied to the communication device for the electronic musical instrument between being taken in from the electronic musical instrument via the input terminal and being taken in from the battery in accordance with a communication state of transmitting and receiving various kinds of electronic information between the electronic musical instrument and the other electronic instrument via the input terminal and the output terminal;
• setting a communication mode capable of switching between a master mode and a slave mode, wherein the master mode is for giving an instruction to the other electronic instrument and the slave mode is for making a response according to an instruction from the other electronic instrument, in which the master mode is set;
• and
• switching electric power to be supplied to the communication device for the electronic musical instrument between being taken in from the electronic musical instrument via the input terminal and being taken in from the battery in accordance with the set communication mode,
• wherein various kinds of electronic information are transmitted and received with respect to the other electronic instrument by wireless communication,
• wherein the wireless communication comprises a first wireless communication step comprising a communication form for transmitting and receiving MIDI data at predetermined time interval, and a second wireless communication step comprising a communication form for transmitting and receiving MIDI data at a time interval shorter than the predetermined time interval of the first wireless communication step, and
• wherein a frequency used in the wireless communication changes in the first wireless communication step.