Data communication method, data communication terminal, data communication system and communication control system

A data communication terminal for use in a data communication system for transmitting and receiving communicated data between communication terminals over a computer network, said data communication terminal comprising:

• address acquiring means for requesting connection to said computer network via a first telephone line in order to acquire a computer network address to identify said data communication terminal on said computer network;
• transmitting means for transmitting communication information including at least said computer network address to another communication terminal via a second telephone line;
• communication controlling means fore acknowledging a connection request sent by said another communication terminal over said first telephone line in order to establish communication between said data communication terminal and said another communication terminal;
• and
• further comprising encrypting means for encrypting transmission data by a predetermined encryption method, wherein the communication information transmitted by said transmitting means to said another communication terminal includes an encryption key for designating said encryption method.

A data communication system for transmitting and receiving communicated data between a first communication terminal and a second communication terminal over a computer network, said first communication terminal comprising:

• means for requesting connection to said computer network via a first telephone line in order to acquire a first computer network address of said first communication terminal;
• means for transmitting communication information including at least said first computer network address to said second communication terminal via a second telephone line;
• and
• said second communication terminal comprising:
• means for connecting to said computer network, upon receipt of the communication information including said first computer network address by said second communication terminal, via said first telephone line in order to acquire a second computer network address of said second communication terminal;
• means for outputting connection information including said first and said second computer network address onto said computer network to request communication with said first communication terminal;
• whereby communication is established between said first and said second communication terminals over said computer network.

A communication control system comprising a remotely controlling center and a remotely controlled terminal, said remotely controlling center controlling said remotely controlled terminal via a computer network, said remotely controlling center comprising:

• means for requesting connection to said computer network via first telephone line in order to acquire a first computer network address of said remotely controlling center;
• means for transmitting communication information including at least said first computer network address to said remotely controlled terminal via a second telephone line;
• and
• said remotely controlled terminal comprising:
• means for requesting connection to said computer network, upon receipt of the information including said first address, via said first telephone line in order to acquire a second computer network address of said remotely controlled terminal;
• means for outputting connection information including said first and said second computer network addresses onto said computer network to request communication with said remotely controlling center;
• whereby communication is established between said remotely controlling center and said remotely controlled terminal over said computer network so that said remotely controlling center may remotely control said remotely controlled terminal.