Bus communication system by unrestrained connection and a communication control method therefor

A line concentrator arranged in a lower tier with respect to a host device managing a bus and transferring communication with said host device, comprising:

• a first functional block operating under a Universal Serial Bus (USB) standard and constructing a virtual port with respect to a port physically provided to said line concentrator and connected a bus device to the virtual port;
• and
• a second functional block operating for performing a response and a setting for the communication transferred to a device connected to the virtual port to take a place of said bus device,
• said line concentrators having a port connected to another concentrator having a port connected to said bus device, each of said line concentrators establishing a function of said first and second functional blocks in accordance with a connection of said line concentrator with said bus device.

A method controlling communication over a bus communication system in which a plurality of line concentrators, each having line concentrating and switching functions, are connected to a host device, and are operated under a Universal Serial Bus (USB) standard, comprising:

• a first step of constructing a virtual port in one line concentrator when another line concentrator is connected to a physical port provided to said one line concentrator and a bus device is connected to said other line concentrator;
• a second step of setting an operation as if said bus device is connected to the virtual port;
• a third step of causing, in setting a bus connection by said host device, said one line concentrator to respond to communication associated with the setting of the bus connection from said host device to said bus device to take a place of said bus device;
• and
• a fourth step of setting the bus connection by communication with said one line concentrator responsive to the response.

A method controlling communication over a network system including a first network formed by a device satisfying a Universal Serial Bus-On-The-Go (USB-OTG) standard, said device of the USB-OTG standard forming said first network being a connection device, and a second network formed by connecting a line concentrator, having a transferring and line-concentrating function and operating on a USB standard, to a port of said connection device and by connecting a device of the USB standard to a port of said line concentrator, said second network being connected to said first network, said method comprising:

• a first step of determining a state of connection and constructing a virtual port distinct from a physical port actually provided to said connection device, subject to a condition that said connection device is located simply as a device;
• a second step of setting said device of the USB standard connected to a port of said line concentrator by a function of said connection device in setting an operation as if said device of the USB standard is connected to the virtual port;
• a third step of detecting data transferred to said device of the USB standard by said connection device, transferring the data to said device of the USB standard responsive to the detection, and responding in proxy for said device of the USB standard;
• and
• a fourth step transferring the data from said connection device to said device of the USB standard subsequent to the response.