Abstract: In a relay device, a control unit detects simultaneous transmission of a plurality of data through a first communication bus. When the number of times of detection of the simultaneous transmission within a predetermined time by the control unit is less than the predetermined number of times, a CAN communication unit starts transmission of data through the first communication bus. When the number of times of detection of the simultaneous transmission within the predetermined time by the control unit is equal to or greater than the predetermined number of times, an Ethernet communication unit transmits data through a first communication line.

Abstract: A communication device includes: a data transmission unit that is connected to a communication bus to which a plurality of communication equipments are connected and transmits data; and a processing unit that performs processing. The order in which the plurality of pieces of communication equipment and the data transmission unit transmit data through the communication bus is determined in advance. A start signal indicating the start of data transmission is repeatedly transmitted through the communication bus. The data transmission unit transmits data according to the order when the start signal is transmitted. The processing unit changes the transmission interval of the start signal.

Abstract: A first ECU and a plurality of second ECUs are connected to a communication bus. The first ECU repeatedly transmits a beacon signal through the communication bus. Each of the first ECU and the plurality of second ECUs transmits data according to an order set in advance when the beacon signal is transmitted. The first ECU or the second ECU transmits dummy data whose transmission destination is different from the remaining ECUs when there is no transmission data to be transmitted to one of the remaining ECUs other than itself.

Abstract: An on-board device includes a processing unit, and a storage unit storing a plurality of programs that are executable by the processing unit, in which the processing unit acquires information relevant to the presence or absence of update that is provided from a server outside a vehicle, stores the acquired information relevant to the presence or absence of the update in a sharing area by executing an input/output function that is different from an input/output function included in a basic program, and selectively executes the basic program or an update processing program after starting execution of a boot program, on the basis of the stored information relevant to the presence or absence of the update.

Abstract: An on-vehicle relay device comprises a control unit selectively executing a control program stored in a storage or an update processing program, and the control unit specifies, in executing the control program, a first communication unit to which any one of the on-vehicle ECUs as a relay destination is connected with reference to network configuration information stored in a storage, specifying, in executing the update processing program, a second communication unit for communicating with an external device that performs update-related processing of the control program with reference to network configuration information stored in the storage; and prohibiting communication through a communication unit other than the specified communication unit.

Abstract: In a relay device, a control unit stores, in a temporary storage unit data which is received by an Ethernet communication unit through a communication line. When the data stored in the temporary storage unit is transmitted, the control unit deletes the transmitted data from the temporary storage unit. When the control unit determines that, for the data received by the Ethernet communication unit, the amount of data stored in the temporary storage unit is equal to or greater than a threshold value, the Ethernet communication unit transmits instruction data giving an instruction to stop transmission through a communication line and to perform transmission through a communication bus.

Abstract: In a relay device, a communication unit receives a data frame transmitted cyclically through a communication line. A control unit stores, in a temporary storage unit, the data frame received by the communication unit. When the data frame stored in the temporary storage unit is transmitted, the control unit deletes the transmitted data frame from the temporary storage unit. When the control unit determines that, for the data frame received through the communication line, the amount of data relevant to the data frames stored in the temporary storage unit is equal to or greater than a threshold value, the communication unit transmits, through the communication line, a cycle change frame which gives an instruction to change a transmission cycle for transmitting the data frame to a longer cycle.

Abstract: In a relay device, a control unit stores, in a temporary storage unit data which is received by an Ethernet communication unit through a communication line. When the data stored in the temporary storage unit is transmitted, the control unit deletes the transmitted data from the temporary storage unit. When the control unit determines that, for the data received by the Ethernet communication unit, the amount of data stored in the temporary storage unit is equal to or greater than a threshold value, the Ethernet communication unit transmits instruction data giving an instruction to stop transmission through a communication line and to perform transmission through a communication bus.

Abstract: In a relay device, a communication unit receives a data frame transmitted cyclically through a communication line. A control unit stores, in a temporary storage unit, the data frame received by the communication unit. When the data frame stored in the temporary storage unit is transmitted, the control unit deletes the transmitted data frame from the temporary storage unit. When the control unit determines that, for the data frame received through the communication line, the amount of data relevant to the data frames stored in the temporary storage unit is equal to or greater than a threshold value, the communication unit transmits, through the communication line, a cycle change frame which gives an instruction to change a transmission cycle for transmitting the data frame to a longer cycle.

Abstract: In a relay device, a control unit detects simultaneous transmission of a plurality of data through a first communication bus. When the number of times of detection of the simultaneous transmission within a predetermined time by the control unit is less than the predetermined number of times, a CAN communication unit starts transmission of data through the first communication bus. When the number of times of detection of the simultaneous transmission within the predetermined time by the control unit is equal to or greater than the predetermined number of times, an Ethernet communication unit transmits data through a first communication line.