A client (such as a PC, portable telephone, PDA, electrical appliances), to which a device such as a IC card is connected, starts a handshake protocol to request a server to start communication. When communication is established via the handshake protocol, the initiative of communication is transferred to the server, and the state changes into a neutral state. In this neutral state, a control packet including a particular number of messages and a finished message is transmitted from the server to the client. If the client receives the control packet, the client performs a process according to the messages included in the control packet. This makes it possible to remotely control a device via a network in a highly reliable and efficient manner.