Data communication system, data communication request device, and data communication response device

A data communication system including first and second devices that are capable of performing full-duplex communication and half-duplex communication via a set of channels connecting the first and second devices, wherein

• full-duplex communication is established at initialization,
• the devices each include an initialization unit operable to enable each other to share selection information at initialization, the selection information helping each device to select either full-duplex communication or half-duplex communication in compliance with a procedure predetermined between the devices,
• the first device includes
• (i) a communication request unit operable to generate a request signal containing a first communication flag and transmit the generated request signal to the second device via the set of channels, the first communication flag indicating whether half-duplex communication is to be specified in accordance with a capability of the first device,
• (ii) a first selection unit operable to receive, from the second device, a response signal containing a second communication flag in response to the request signal and select either the full-duplex communication scheme or the half-duplex communication scheme depending on the first communication flag, the second communication flag, and the selection information in compliance with the procedure, the second communication flag indicating whether half-duplex communication is to be specified in accordance with a capability of the second device, and the selected communication scheme conforming to the capability of each device, and
• (iii) a first communication unit operable to perform data communication in the selected communication scheme, and
• the second device includes
• (i) a communication response unit operable to generate the response signal containing the second communication flag in response to the received request signal and transmit the generated response signal to the first device via the set of channels,
• (ii) a second selection unit operable to select either the full-duplex communication scheme or the half-duplex communication scheme depending on the first communication flag, the second communication flag, and the selection information in compliance with the procedure, the selected communication scheme conforming to the capability of each device, and
• (iii) a second communication unit operable to perform data communication in the selected communication scheme.

A data communication request device that transmits a data communication request to an other device via a set of channels connecting the data communication request device and the other device, which are capable of performing full-duplex communication and half-duplex communication, comprising:

• an initialization unit operable to enable the data communication request device and the other device to share selection information at initialization where full-duplex communication is established, the selection information helping each device to select either full-duplex communication or half-duplex communication in compliance with a procedure predetermined between the devices;
• a communication request unit operable to generate a request signal containing a first communication flag and transmit the generated request signal to the other device via the set of channels, the first communication flag indicating whether half-duplex communication is to be specified in accordance with a capability of the data communication request device;
• a selection unit operable to receive, from the other device, a response signal containing a second communication flag in response to the request signal, and select either a full-duplex communication scheme or a half-duplex communication scheme depending on the first communication flag, the second communication flag, and the selection information in compliance with the procedure, the second communication flag indicating whether half-duplex communication is to be specified in accordance with a capability of the other device, and the selected communication scheme conforming to the capability of each device;
• and
• a communication unit operable to perform data communication in the selected communication scheme.

A data communication response device that receives a data communication request from an other device via a set of channels connecting the data communication response device and the other device, which are capable of performing full-duplex communication and half-duplex communication, comprising:

• an initialization unit operable to enable the data communication response device and the other device to share selection information at initialization where full-duplex communication is established, the selection information helping each device to select either full-duplex communication or half-duplex communication in compliance with a procedure predetermined between the devices;
• a communication response unit operable to receive, from the other device, a request signal containing a first communication flag, generate a response flag containing a second communication flag, and transmit the generated response signal to the other device via the set of channels, the first communication flag indicating whether half-duplex communication is to be specified in accordance with a capability of the other device, the second communication flag indicating whether half-duplex communication is to be specified in accordance with a capability of the data communication response device;
• a selection unit operable to select either a full-duplex communication scheme or a half-duplex communication scheme depending on the first communication flag, the second communication flag, and the selection information in compliance with the procedure;
• and
• a communication unit operable to perform data communication in the selected communication scheme.

A communication method used in a data communication system, the data communication system including first and second devices that are capable of performing full-duplex communication and half-duplex communication via a set of channels connecting the first and second devices, wherein

• full-duplex communication is established at initialization,
• the devices each perform initialization processing of communication, which enables each other to share selection information at initialization where full-duplex communication is established, the selection information helping each device to select either full-duplex communication or half-duplex communication in compliance with a procedure predetermined between the devices,
• the first device includes the steps of
• generating a request signal containing a first communication flag, and transmitting the generated request signal to the second device via the set of channels, the first communication flag indicating whether half-duplex communication is to be specified in accordance with a capability of the first device,
• receiving, from the second device, a response signal containing a second communication flag in response to the request signal, and selecting either the full-duplex communication scheme or the half-duplex communication scheme depending on the first communication flag, the second communication flag, and the selection information in compliance with the procedure, the second communication flag indicating whether half-duplex communication is to be specified in accordance with a capability of the second device, the selected communication scheme conforming to the capability of each device, and
• performing data communication in the selected communication scheme, and
• the second device includes the steps of
• generating the response signal containing the second communication flag in response to the received request signal, and transmitting the generated response signal to the first device via the set of channels,
• selecting either the full-duplex communication scheme or the half-duplex communication scheme depending on the first communication flag, the second communication flag, and the selection information in compliance with the procedure, the selected communication scheme conforming to the capability of each device, and
• performing data communication in the selected communication scheme.