Abstract: An IP telephone system includes a first IP telephone terminal and a second IP telephone terminal. IP telephone communications are established between the first and second IP telephone terminals via Internet when the second IP telephone terminal has acquired identification data identifying the first IP telephone terminal. The second IP telephone terminal further acquires terminal data identifying a function that the first IP telephone terminal can control via Internet. The first IP telephone terminal receives from the second IP telephone terminal data instructing to execute the function that the first IP telephone terminal can control. Then, the first IP telephone terminal controls execution of the function identified by the data received from the second IP telephone terminal.