Communication device, communication system, communication method, and communication circuit

A communication device, serving as a secondary station which carries out communication with a primary station, comprising:

• a first protocol control section for, without transmitting a station-search response to a station-search command, transmitted from the primary station to confirm a presence of the secondary station, so that a connection is established, when receiving a first connection request command from the primary station, transmitting a connection response to the first connection request command, so that a connection is established;
• a second protocol control section for transmitting a station-search response to a station-search command from the primary station, and then transmitting a connection response to a second connection request command, so that a connection is established;
• and
• a protocol switching section for causing the second protocol control section to transmit the station-search response, when the communication device receives two or more of the station-search commands in which whole slot numbers are set to 1, or receives one of the station-search commands in which whole slot numbers are set to a number other than 1, without receiving the first connection request command from the primary station.

A communication system, comprising a communication device serving as a primary station and a communication device serving as a secondary station which carries out communication with the primary station, said communication device serving as the primary station gets connected with the secondary station using an SNRM frame, the SNRM frame being a transmission/reception frame used in IrLAP (Infrared Link Access Protocol) and having a control field set to an SNRM (Set Normal Response Mode),

• said communication device serving as the primary station transmitting the SNRM frame in which information indicative of any secondary station is assigned to a destination address field which is a component of a frame obtained by adding to the SNRM frame used in IrLAP a field to which upper layer data is to be written, so as to establish a connection with the secondary stations;
• said communication device serving as the secondary station comprising:
• a first protocol control section for, when receiving a first connection request command from the primary station, transmitting a connection response to the first connection request command, so that a connection is established;
• a second protocol control section for transmitting a station-search response to a station-search command from the primary station, and then transmitting a connection response to a second connection request command, so that a connection is established;
• and
• a protocol switching section for causing the second protocol control section to transmit the station-search response, when the communication device serving as the secondary station receives two or more of the station-search commands in which whole slot numbers are set to 1, or receives one of the station-search commands in which whole slot numbers are set to a number other than 1, without receiving the first connection request command from the primary station.