By making the most of the master and slave roles, the master device becomes the system controller to manage the control functions of the slave devices in a piconet. For one slave device to control another slave device, the controlling slave device issues a command to the master device, which transfers the received command to the controlled slave device. Each slave device control other slave devices in a piconet without being aware of other slave devices except the master device. Consequently, commands may be exchanged between the slave devices in a piconet which is constituted by one master device and a plurality of slave devices.