An electronic organ 1 and a personal computer 2 are connected with a MIDI cable. The personal computer 2 is connected to a server 4 via a communication network 3. The personal computer 2 downloads a controlling program from the server 4. The electronic organ 1 is set to be a listening trial mode by an operation of the personal computer 2. In the listening trial mode, an output of a data in a temporally storage area is prohibited. The server 4 provides a first encoded performance data to the personal computer 2, and the personal computer 2 decodes the received first encoded performance data. The electronic organ 1 generates a key, and the personal computer 2 secondary encodes the performance data with the key and transmits it to the electronic organ 1. The electronic organ 1 deletes the data stored in the temporally storage area after the listening trial.