Abstract: The other communication devices are prohibited to transmit the address initialization request for a prescribed period of time since one communication device transmitted the address initialization request for an address managed by a control protocol, so that the conflict of the initialization requests for the same address will not occur and the problem of assigning the address in overlap to the communication devices will not arise. Also, the other communication devices are prohibited to transmit the the address server detection request packet for a prescribed period of time since one communication device transmitted the address server detection request packet, so that the conflict on the network by a plurality of address server detection requests will not occur, and it is possible to determine the MAC address server uniquely.

Abstract: A communication device that stores a secret key to be used in an authentication and an encryption of communication information with respect to a specific communication device, and carries out communications with the specific communication device, by using the stored secret key to be used with respect to the specific communication device, is equipped with a unit for updating a specific secret key, when an update request received from another communication device is requesting a secret key updating, according to an update content given along with the update request which indicates the specific secret key.

Abstract: In a communication device for carrying out communications according to an Echonet protocol on a network of a prescribed network layer protocol, a prescribed bit sequence value of a network layer address or a datalink layer address of the communication device is set as a candidate for an Echonet address to be used in the Echonet protocol. Then, an inquiry packet for inquiring whether the prescribed bit sequence value is identical to the Echonet address used by each other communication device or not is transmitted, and the prescribed bit sequence value is determined as the Echonet address of the communication device when the prescribed bit sequence value is judged as not identical to any of Echonet addresses used by the other communication devices.

Abstract: A digital home electronic device is provided with a storing unit for storing correspondence data formed by corresponding sets of commands corresponding to classification informations for classifying a plurality of commands according to prescribed criteria, and a target device information indicating a target device which enables the digital home electronic device to execute the commands, and a command execution judgement unit for judging whether or not to execute a received command, according to the received command, a source information indicating a device which is a source of the received command, and the correspondence data, by judging whether the source information and the target device information corresponding to the received command coincide or not.

Abstract: In order to make it possible to enable the operation of a control protocol such as Echonet on networks such Bluetooth, IP, etc., a communication control device carries out a routing processing according to an address table that stores in correspondence a Bluetooth address and a slave identifier of a Bluetooth, and an Echonet address of an Echonet protocol, for example. Also, a communication device carries out a transmission/reception processing of an IP packet according to an address table that stores in correspondence an IP address of the Internet protocol and an Echonet address of the Echonet protocol, for example.