JP4087366B2 - COMMUNICATION DEVICE, COMMUNICATION SYSTEM, AND COMMUNICATION METHOD - Google Patents

Description

  The present invention relates to a communication apparatus, a communication system, and a communication method for performing communication using a predetermined control protocol on a network such as an echo net.

  In recent years, development of so-called information home appliances in which communication functions are provided in white appliances such as refrigerators and washing machines, information appliances such as AV home appliances and personal computers, and mobile devices such as mobile phones has been actively performed. Various functions using digital technology have been proposed for each device.

  One application of information appliances is the use of home networks. The home network is a network technology in the home, and performs communication by connecting the various information appliances described above to each other.

  As this type of home network technology, the Internet technology has attracted particular attention recently. For example, applications that are attractive to home network users, such as music distribution, homepage browsing, and e-mail, have been developed one after another, and the number of users continues to increase.

  On the other hand, one application example of a home network is use as an equipment network or home automation. These networks are connected to air conditioners, lighting, white goods, etc., and device status monitoring, remote control, etc. can be considered as applications.

Echonet is expected to become the de facto standard in Japan for this type of equipment network. Echonet defines commands, protocols, objects, APIs, etc. for controlling equipment devices (white goods, etc.) on various physical media such as electric light wires and twisted pair wires (for example, non-patented) Reference 1). This Echonet is standardized by a consortium established mainly by a number of electrical manufacturers in Japan, and version 1 specifications have already been issued and commercialization is about to begin.
JP 2000-183941 A http://www.echonet.or.jp

  The Echonet itself has an address system, and it is necessary to devise such that the “Echonet” address system is placed on top of the “Internet” address system. Since the echonet address is a logical address, it is necessary to perform a determination procedure for determining the echonet address when the device is turned on.

  However, since the determination of the Echonet address is an initialization procedure that must be performed by all nodes, “What should I do if there are multiple nodes that want to use the same address at the time of initialization?” Or, not only when determining addresses, but when deciding on a specific server, for example, "What should I do if multiple nodes try to become specific servers at the same time?" There is a possibility that a conflict problem occurs, and in the worst case, an address or a server overlaps or the initialization process is repeated infinitely.

  A known method has been proposed for determining an address used for communication (see Patent Document 1).

  The present invention has been made in consideration of the above circumstances, and provides a communication device, a communication system, and a communication method having an appropriate arbitration mechanism even when a conflict occurs at the time of address initialization or server setting. With the goal.

  According to one aspect of the present invention, a communication device that communicates with another communication device using a predetermined control protocol on a network, and determines an address managed on the predetermined control protocol A server request transmission unit that broadcasts an address server detection request packet for requesting to become an address server having an authority to perform the transmission on the network, and a first after transmitting the address server detection request packet. If a packet from another communication device indicating that it is an address server is not received within a predetermined time, a server determination unit that determines the own device as an address server, and after sending the address server detection request packet, When an address server detection request packet transmitted from another communication device is received, the address server detection request packet is Communication device, characterized in that it comprises first and said control unit for controlling the server request transmission unit such that the second to the transmission again broadcast after a predetermined time longer than the predetermined time, is provided.

  According to the present invention, since a certain communication device broadcasts the address server detection request packet and the other communication device does not broadcast the packet within a predetermined time, the address server detection request is transmitted on the network. This eliminates the conflict and can uniquely determine the address server.

  Hereinafter, a communication apparatus, a communication system, and a communication method according to the present invention will be specifically described with reference to the drawings.

  In the following, a case where the Echonet protocol is mapped on the Internet protocol (hereinafter, IP) and the Echonet protocol is operated on the IP network will be described as an example. The specific type of IP is not particularly limited, and may be IPv4 or IPv6.

  In the present embodiment, a configuration in which each node (for example, various so-called white goods and its controller) is connected by a local wireless network technology called Bluetooth ™ will be described as an example. Here, BluetoothTM is a local wireless network characterized by low cost and low power consumption. For example, see http://www.Bluetooth.com.

  On Bluetooth, the PAN (Personal Area Network) profile defines the “IP over Bluetooth” method. In the present embodiment, an example in which this method is used will be described. Here, PAN is an Ethernet (registered trademark) emulation standard defined on Bluetooth, and by using this mechanism, an Ethernet (registered trademark) frame can be exchanged on Bluetooth.

  FIG. 1 is a block diagram showing a schematic configuration of an embodiment of a home network system according to the present invention. The home network system of FIG. 1 includes a base station (hereinafter also referred to as a PAN base station) 1 that communicates with each other using Bluetooth, and a plurality of echo net devices 2 (A, B, and C in FIG. 1). ing.

  A base station (also referred to as a PAN base station) 1 is a Bluetooth piconet master. The Bluetooth base station 1 of the present embodiment is described as not being an echonet node (however, the Bluetooth base station 1 may be an echonet node).

  The echo net device 2 may be any device such as a home appliance, an AV device, a personal computer or other information device as long as it supports the echo net.

  The Bluetooth base station 1 may have a function of controlling (or monitoring) the echo net device 2 through Bluetooth. Further, another node (not shown) may have a function of controlling (or monitoring) the echo net device 2 through Bluetooth.

  All these devices (in FIG. 1, base station 1, devices A, B, and C) each have an IP address. The IP address may be an IPv4 address or an IPv6 address. Here, description will be made assuming that the IP address is a private address or a link local address. A private address is an address that uses an address space that is permitted to be used only in a private network space, and addresses may overlap with networks in other regions. On the other hand, the link local address is a special IP address that can be used only on the link (Bluetooth in this example).

  In the private address, communication in the direction of “private address => global IP address” is possible, but communication in the reverse direction is impossible. On the other hand, communication with a global IP address is impossible with a link local address. While there is no need to give a globally unique IP address as both addresses for communication, this is a method used when operating a specific application of IP on a local network (link network).

  Since the Echonet protocol is a protocol developed on the premise and target of a local network, it is possible to use a private address or a link local address even on the IP, and by using these addresses, the home network can be used in advance. It is possible to prevent malicious access and erroneous access to the home appliances and Echonet operating range from outside.

  FIG. 2 is a diagram showing an example of the internal configuration of the echo net device 2. As shown in FIG. 2, the Echonet device 2 includes a Bluetooth interface 11 for wireless communication by Bluetooth, an Echonet processing unit 12 that performs Echonet processing, and another protocol processing unit that performs predetermined protocol processing. 13.

  The echo net processing unit 12 includes an Ethernet frame transmission / reception unit 21 for exchanging Ethernet frames with the Bluetooth interface 11, an Internet processing unit 22 for exchanging Internet packets, and an initialization process for echo net on IP / Bluetooth. , An address resolution unit 24 that performs address resolution between the echo net address and the IP address, an address table 25 that stores the IP address and the echo net address in association with each other, An echo net control processing unit 26 that performs command processing and middleware processing in general, and a user interface 27 that includes a liquid crystal screen, a touch panel, a keyboard, and the like.

  FIG. 3 is a diagram showing an example of the internal structure of the address table 25. As shown in FIG. 3A, the address table 25 of the present embodiment includes an IP address of an Echonet node in the IP subnet (specifically, the link local space) (in this embodiment, The private address or link local address) and the echo net address (the MAC address or node ID (node identifier)) of the node are stored in association with each other.

  Further, as shown in FIG. 3B, the echo net device 2 has a table for holding an echo net MAC address group already used by another echo net device 2 at a certain time.

  Here, the Echonet MAC address is an 8-bit logical identifier, and its specification is defined in the Echonet specification. In the Echonet specification, a network identifier, which is a net ID, is also defined. In this embodiment, the net ID is assumed to be fixed, and description will be made focusing on the node ID or MAC address assigned to each node. This value may also be assigned a different value depending on circumstances.

  In FIG. 3A, the subscript 0 indicates the one corresponding to the Bluetooth base station 1 in FIG. 1, and the subscripts a and b indicate the ones corresponding to the echo net devices A and B in FIG. Show.

  In the present embodiment, the internal structure of the Bluetooth base station 1 when the Bluetooth base station (PAN base station) 1 is an echonet node is basically the same as the internal structure of the echonet device 2. However, the Ethernet frame transmitting / receiving unit 21 in the Bluetooth base station 1 has a function of performing an Ethernet frame routing (an Ethernet frame routing unit). The ether frame routing unit checks whether the received ether frame is destined for the own node. If it is not destined for the own node, the ether frame is transmitted to the destination. Then, by referring to the Ether type field, it is transferred to the corresponding processing unit inside. In this case, the value of the echo net MAC address of the base station 1 that is an echo net node may be a fixed value such as 0 or 1, for example.

  As in the Bluetooth of this embodiment, the node standing at the position of the Bluetooth master plays a special role as an echonet node (such as Ethernet frame routing, address resolution, initialization processing, etc.). It is possible to simplify the processing by assigning a fixed number.

  Hereinafter, an Echonet MAC address initialization procedure will be described.

  FIG. 4 is a diagram illustrating an example of an initialization sequence of an echo net MAC address, and FIG. 5 is a diagram illustrating an example of a processing procedure for determining an initial value (temporary MAC address) of an echo net MAC address.

  Here, a part of the hardware address, for example, the value of the lower 8 bits of the own Bluetooth address is used as the Echonet MAC address. If there is a node with the same part of the hardware address in the same subnet, if this value is used, the value of the Echonet MAC address will be duplicated in the subnet. In such a case, the own Echonet MAC address is determined by avoiding duplication of Echonet MAC addresses by the method described below.

  Assume that the Echonet device A and Echonet device B initially belong to a piconet in which the PAN base station 1 is a Bluetooth master (hereinafter referred to as BT master). In other words, it is assumed that there are two echonet nodes, device A and device B, in this piconet at this time. An example will be described in which the Echonet device C tries to join this piconet in such a state.

  As shown in FIG. 5, the Echonet device C determines whether or not the MAC address at the previous operation is held (step S51). If it is held, the MAC address used last time is set as the temporary MAC address. (Step S52) If not held, the lower 8 bits of its own hardware address are set as a temporary MAC address (Step S53).

  FIG. 4 illustrates an example in which the value of the Echonet MAC address used last time is a temporary MAC address (step S1).

  The Echonet device C broadcasts a MAC address initialization request packet including the value of the lower 8 bits of the hardware address to the local link (may be an IP multicast address assigned to the Echonet node), and The duplication of the net address value is investigated (steps S2 to S4). This packet may be transmitted a plurality of times in order to prevent this packet from reaching due to the state of radio waves in the network, the state of the receiving node, and the like. In the case of the present embodiment, a case where transmission is performed twice is illustrated (steps S5 to S7).

  This MAC address initialization request packet has three meanings. The first is to detect a MAC address server existing on the network. Here, the MAC address server is a server node that assigns a MAC address value in response to a request. For details, refer to the second embodiment described later. The second meaning is to check whether or not there is a node on the network that is going to use the value of its own temporary MAC address. The third meaning is to know the correspondence between the IP address, Echonet MAC address, and hardware address of the Echonet device 2 on the network.

  Other nodes that have received a MAC address initialization request or a MAC address confirmation request packet, which will be described later, transmitted from the Echonet device C do not send the MAC address initialization request for T2 + random time (steps S8 and S9). In the echo net device C, there are other echo net nodes using the same MAC address, or MAC address initialization requests and MAC address confirmation requests regarding the same MAC address from other echo net devices A and B. Unless T2 is received, the temporary MAC address is determined as its own MAC address within the T2 + random time described above.

  Thereby, the vibration at the time of MAC address determination can be prevented beforehand. That is, when a certain device P intends to use a specific MAC address, another device Q takes away the right to use the specific MAC address, or conversely, the right to use the MAC address of the other device Q. Can be prevented from being repeatedly taken by the device P.

  If all the nodes on the network respond simultaneously to the reception of the MAC address initialization request packet, congestion occurs at the transmission node (Echonet device C). Therefore, each Echonet device A, B, C waits for a time obtained by multiplying the value of its own Echonet MAC address by time T1, and returns a response to the MAC address initialization request, thereby returning the Echonet device. The congestion of the signal received by the device C is prevented beforehand (steps S10 and S11).

  After the time specified in steps S10 and S11, the echo net device 2 that has received the MAC address initialization request packet returns its own MAC address using the MAC address initialization response packet (steps S12 to S12). S15). At this time, the IP address and hardware address are also returned simultaneously. The reason for returning its own MAC address is to check whether the second and third reasons described above, that is, whether or not there is a node on the network that is trying to use the value of its own temporary MAC address. The third is to know the correspondence relationship between the IP address, Echonet MAC address, and hardware address of the Echonet device 2 on the network.

  The MAC address initialization response packet may be loaded with “a MAC address value that should not be used”. In the figure, it is written as “in-use MAC address”. This value is the MAC address of the Echonet node on the network that is currently known by the node that is sending this packet, or the MAC address of the Echonet node that has been operating within a certain period of time. May not be installed). If the MAC address of the Echonet node that is not operating at that time is installed, the MAC address that has passed for a certain period of time after confirming that it is not operating will be used as the value of the “MAC address in use”. Do not install.

  If the Echonet device C does not return a MAC address initialization response packet indicating that it uses the same Echonet MAC address (node ID) as the inquired value for a certain period of time (T2 time), there will be no overlap. Then, a MAC address confirmation request packet for reconfirming the presence / absence of the node using the temporary MAC address value is broadcast to the network (step S17). Here, if the response packet is not transferred to the MAC address confirmation request packet for a certain time (T2 time), it is determined that there is no duplication of the MAC address in the network, and the value of the temporary MAC address is determined by the own device. The Echonet MAC address (node ID) to be used is determined (step S19). This determination is made after waiting for T2 time after transmitting the last MAC address initialization request packet (step S18). Here, the value of T2 is a product value of the maximum number of Echonet devices 2 that can exist on the network and T1 time.

  FIG. 6 is a diagram showing a processing procedure when another echonet device already uses the same address as the temporary MAC address transmitted by the echonet device C.

  In steps S61 to S74 in FIG. 6, the same processes as in steps S1 to S6 and S10 to S16 in FIG. 4 are performed. However, in step S61, MACa which is the Echonet MAC address of Echonet device A is set as a temporary MAC address.

  When the Echonet device C recognizes that another node (Echonet device A) is using the same MAC address (Step S75), it determines its own temporary MAC address from the unused address (Step S75). S76). Here, MACc is determined as a temporary MAC address.

  Next, the MAC address confirmation request is broadcast twice to other nodes (Echonet devices A and B) (steps S77 to S82). Next, after waiting for a predetermined time T2 (step S83), it is confirmed that MACc is not used, and its own Echonet MAC address is determined to be MACc (step S84).

  On the other hand, the Echonet device C also transmits a MAC address initialization request for the temporary MAC address = MACc, and from another node on the network within “T2 time”, the “MAC address for the temporary MAC address = MACc”. An initialization request or a MAC address confirmation request (described later) may be received. In this case, it is necessary for the echo net device C to cancel the transmitted MAC address initialization request, wait for T2 + random time or more, and then perform this again from the step of transmitting the MAC address initialization request. As the new temporary MAC address selected at this time, it is desirable to select a value different from the previously selected value in order to reduce the MAC address duplication probability. Also, avoid using this value as a new temporary MAC address for a temporary MAC address requested by a MAC address initialization request or a MAC address confirmation request (described later) received while waiting for T2 time. I will do it.

  FIG. 7 is a state transition diagram summarizing the processing procedures of FIGS. 4 to 6 described above. First, a temporary MAC address is determined according to the algorithm of FIG. 5 (step S91), and a random time is waited (step S92). Thereafter, a MAC address initialization request is sent (step S93), and a time T2 is waited (step S94).

  When a MAC address initialization response indicating that another node is using the same MAC address is received, the temporary MAC address is changed (step S96), and a MAC address confirmation request is transmitted (step S97).

  After that, the system waits for time T2 (step S98). When a MAC address confirmation response indicating that another node is using the same MAC address is received while waiting, the processing of steps S96 to S98 is repeated. On the other hand, if there is no confirmation response from the other node that the same MAC address is used even after waiting for time T2 in step S97, the temporary MAC address is determined as the MAC address (step S99).

  As can be seen from the state transition diagram of FIG. 7, the temporary MAC address is repeatedly changed as long as there is an acknowledgment from the other nodes that the same MAC address is used. Is preferably stored in an internal memory area or the like.

  As described above, in the first embodiment, since the address initialization request cannot be transmitted for a predetermined period after another node on the network receives the MAC address initialization request, the initial value for the same MAC address is set. Requests do not conflict, and there is no problem that addresses are assigned redundantly. In addition, when there is a node that transmits a MAC address initialization request packet or a MAC address confirmation request packet for the same MAC address at the same time, at least one node (or both nodes) that receives the packet transmits As described above, since the MAC address determination procedure is temporarily suspended and the address initialization request cannot be transmitted for a predetermined time, the MAC address of the other node is expected to be determined in the meantime. Can be prevented in advance.

  Since each node that has received the address initialization request does not transmit an address initialization response until the MAC address value × predetermined time T1 has elapsed after receiving this request, a plurality of responses are received. Can be prevented from being received in conflict.

(Second Embodiment)
The second embodiment prevents contention when a MAC address server is determined.

  In the Echonet of the second embodiment, there is a node having the authority to give an Echonet node that has requested the Echonet MAC address. Such a node is called a MAC address server.

  When there is a MAC address server, the MAC address server that has received the MAC address initialization request packet according to the first embodiment transmits the node (this embodiment) to the node that has transmitted the MAC address initialization request packet. In the case of the form, the value of the MAC address to be used by the echonet device C) is returned. Only one MAC address server may exist in one network (within the Eco-net subnet).

  In the following, a processing procedure when an arbitrary node on the network tries to become the MAC address server will be described. FIG. 8 is a diagram showing a processing procedure when a certain node (here, Echonet device C) tries to become a MAC address server.

  The node desiring to become a MAC address server (S111) first broadcasts a MAC address server detection request packet a plurality of times in order to confirm whether a MAC address server already exists in the network (S112). ~ S117).

  At this point, the node that is already the MAC address server responds to this packet by unicast (or broadcast), notifying that the MAC address server is already in the network. The Echonet device C that has received this packet gives up at this point to become a MAC address server.

  On the other hand, when waiting for time T3 and there is no “MAC address server detection response” from the MAC address server, it is determined that there is no MAC address server in the subnet (S118). In that case, it is assumed that the node has obtained the right to become a MAC address server, notifies the fact within the subnet (step S119), and sends the MAC address server notification packet to the network a plurality of times (3 in this embodiment). Times) (S120 to S128).

  Here, it is assumed that another node that has received this MAC address server detection request packet becomes a MAC address server, that is, cannot transmit a MAC address server detection request packet for T3 + random time. (S129, S130). Within this time, when the Echonet device C becomes a MAC address server, it can transmit a MAC address server notification packet. By doing so, the vibration at the time of determining the MAC address server (after a certain device P tries to become a MAC address server and transmits a MAC address server detection request packet, another device Q is still connected to the MAC address server. The MAC address server detection request packet is transmitted to deprive the right of the device P. Further, the device P deprives the right of the device Q. (This is repeated).

  Here, when the Echonet device C transmits a MAC address server detection request, it may receive a MAC address server detection request transmitted by another node on the network. For example, when two or more nodes are simultaneously trying to become MAC address servers. Also in this case, the Echonet device C needs to cancel the transmitted MAC address server detection request packet, wait for T3 + random time or longer, and then perform this again from the step of transmitting the MAC address server detection request. Through the above processing, the Echonet device C becomes a MAC address server.

  As described above, in the second embodiment, since the MAC address server detection request is prohibited from being transmitted until the predetermined time T3 + random time elapses after the MAC address server detection request is received, The detection request does not compete on the echo net, and the MAC address server can be uniquely determined.

  In the above description, the ECHONET protocol is used as a protocol for controlling devices connected to the network. However, the present invention is not limited to this, and the present invention can be applied to various other control protocols.

  In the above, Bluetooth or IP (IP over Bluetooth) is taken as an example of the local area network, but the present invention is applicable to other types of networks.

  In the above description, the home network has been described as an example of the local area network. However, the present invention can be similarly applied to other local networks such as a corporate network.

  The communication device described above may be configured by hardware or software. When configured by software, a program for realizing the function of the communication device may be stored in a recording medium such as a floppy disk or a CD-ROM and read and executed by a computer. The recording medium is not limited to a portable medium such as a magnetic disk or an optical disk, but may be a fixed recording medium such as a hard disk device or a memory.

  Further, a program for realizing the functions of the communication device described above may be distributed via a communication line (including wireless communication) such as the Internet. Furthermore, the program may be distributed through being stored in a recording medium via a wired line or a wireless line such as the Internet in a state where the program is encrypted, modulated, or compressed.

  Note that the configuration illustrated in the embodiment of the present invention is an example, and is not intended to exclude other configurations, and a part of the illustrated configuration may be replaced with another or one of the illustrated configurations. Other configurations obtained by omitting a part, adding another function or element to the illustrated configuration, or combining them are also possible. Also, another configuration that is logically equivalent to the exemplified configuration, another configuration that includes a portion that is logically equivalent to the exemplified configuration, another configuration that is logically equivalent to the main part of the illustrated configuration, and the like are possible. is there. Further, another configuration that achieves the same or similar purpose as the illustrated configuration, another configuration that achieves the same or similar effect as the illustrated configuration, and the like are possible.

  In addition, various variations of various components illustrated in the embodiment of the present invention can be implemented in appropriate combination.

  Further, the embodiment of the present invention is an invention of an invention as an individual device, an invention of two or more related devices, an invention of the entire system, an invention of components within an individual device, or a method corresponding thereto. The invention includes inventions according to various viewpoints, stages, concepts, or categories.

  Therefore, the present invention can be extracted from the contents disclosed in the embodiments of the present invention without being limited to the exemplified configuration.

  The present invention is not limited to the embodiment described above, and can be implemented with various modifications within the technical scope thereof.

1 is a block diagram showing a schematic configuration of an embodiment of a home network system according to the present invention. The figure which shows an example of the internal structure of an echo net apparatus. The figure which shows an example of the internal structure of an address table. The figure which shows an example of the initialization sequence of an echo net MAC address. The figure which shows an example of the process sequence which determines the initial value (temporary MAC address) of an echo net MAC address. The figure which shows the process sequence in case another Echonet apparatus has already used the same address as the temporary MAC address which Echonet apparatus C transmitted. FIG. 7 is a state transition diagram summarizing the processing procedures of FIGS. The figure which shows the process sequence when a certain node tries to become a MAC address server.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 PAN base station 2 Echonet apparatus 11 Bluetooth interface 12 Echonet process part 13 Other protocol process part 21 Ether frame transmission / reception part 22 Internet process part 23 Initialization process part 24 Address resolution part 25 Address table 26 Echonet control process part 27 User interface

Claims (6)

A communication device that communicates with other communication devices using a predetermined control protocol on a network,
A server request transmission unit that broadcasts on the network an address server detection request packet for requesting to become an address server having authority to determine an address managed on the predetermined control protocol;
A server that determines its own device as an address server if a packet from another communication device indicating that it is an address server is not received within a first predetermined time after broadcasting the address server detection request packet. A decision unit;
When the address server detection request packet transmitted from another communication apparatus is received after the address server detection request packet is broadcast, the address server detection request packet is sent to the second longer than the first predetermined time. And a control unit that controls the server request transmission unit so as to perform broadcast transmission again after a predetermined time .   The communication apparatus according to claim 1, wherein the address server detection request packet is broadcast on the network a plurality of times. A communication system in which a plurality of communication devices communicate with each other using a predetermined control protocol on a network,
At least one of the plurality of communication devices is
A server request transmission unit that broadcasts on the network an address server detection request packet for requesting to become an address server having authority to determine an address managed on the predetermined control protocol;
A server that determines its own device as an address server if a packet from another communication device indicating that it is an address server is not received within a first predetermined time after broadcasting the address server detection request packet. A decision unit;
When the address server detection request packet transmitted from another communication apparatus is received after the address server detection request packet is broadcast, the address server detection request packet is sent to the second longer than the first predetermined time. And a control unit that controls the server request transmission unit so as to perform broadcast transmission again after a predetermined time .   4. The communication system according to claim 3, wherein the predetermined control protocol is an Echonet protocol. A communication method in which a plurality of communication devices and the plurality of communication devices communicate with each other using a predetermined control protocol on a network,
Broadcast on the network an address server detection request packet for requesting to become an address server having authority to determine an address managed on the predetermined control protocol;
If a packet from another communication device indicating an address server is not received within a first predetermined time after broadcasting the address server detection request packet, the communication device that performed the broadcast transmission As the address server,
When the communication device receives the address server detection request packet transmitted from another communication device after broadcast transmission of the address server detection request packet, the communication device transmits the address server detection request packet from the first predetermined time. A broadcast method characterized in that broadcast transmission is performed again after a long second predetermined time .   6. The communication method according to claim 5, wherein the predetermined control protocol is an Echonet protocol.

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