Abstract: A gain switching determination circuit (250) compares/determines a comparative input voltage (Vc) from an inter-stage buffer (230) with a first hysteresis characteristic, and outputs a gain switching signal (SEL) based on the comparison/determination result to first and second transimpedance amplifier core circuits (210, 220), thereby switching the gains of the core circuits. This obviates holding a comparison input voltage with long response time in a level holding circuit for gain switching determination, which allows instantaneous gain switching determination and instantaneous response corresponding to burst data.

Abstract: A switch 1 having a tag VLAN function includes a plurality of physical ports P1, P2 . . . , and adds an ID tag unique to each physical port to the header of a packet received by the physical port and sends the packet, and on the other hand, refers to an ID tag attached to a packet received from a GW 2 and sends the packet to a physical port corresponding to the ID tag. The GW 2 searches for a server address corresponding to the ID tag attached to the packet received from the switch 1 and modifies a destination address of the packet into the server address. In addition, the GW 2 attaches an ID tag corresponding to a source address of the packet received from the shared server 3 to the received packet, and modifies the source address of the packet into a GW address.

Abstract: An administrator 4 (2) registers configuration files of compliant equipment 31 and noncompliant equipment 32 and a configuration script into a management server, and (3) sends the network equipment to a user 33. When the user 33 constructs the local network 3 by connecting the network equipment and turns it on, (4) a configuration request message is transmitted from the compliant equipment 31 to the management server 2. (5) The management server 2 replies with the configuration file of the compliant equipment 31, the configuration file of the noncompliant equipment 32, and the compliant script to the compliant equipment 31 in response to the configuration request. The compliant equipment 31 (6) registers its own configuration file received from the management server 2 into itself, and then (7) configures the configuration file of the noncompliant equipment 32 into the noncompliant equipment by executing the received configuration script.

Abstract: A switch 1 having a tag VLAN function includes a plurality of physical ports P1, P2 . . . , and adds an ID tag unique to each physical port to the header of a packet received by the physical port and sends the packet, and on the other hand, refers to an ID tag attached to a packet received from a GW 2 and sends the packet to a physical port corresponding to the ID tag. The GW 2 searches for a server address corresponding to the ID tag attached to the packet received from the switch 1 and modifies a destination address of the packet into the server address. In addition, the GW 2 attaches an ID tag corresponding to a source address of the packet received from the shared server 3 to the received packet, and modifies the source address of the packet into a GW address.

Abstract: An administrator 4 (2) registers configuration files of compliant equipment 31 and noncompliant equipment 32 and a configuration script into a management server, and (3) sends the network equipment to a user 33. When the user 33 constructs the local network 3 by connecting the network equipment and turns it on, (4) a configuration request message is transmitted from the compliant equipment 31 to the management server 2. (5) The management server 2 replies with the configuration file of the compliant equipment 31, the configuration file of the noncompliant equipment 32, and the compliant script to the compliant equipment 31 in response to the configuration request. The compliant equipment 31 (6) registers its own configuration file received from the management server 2 into itself, and then (7) configures the configuration file of the noncompliant equipment 32 into the noncompliant equipment by executing the received configuration script.

Abstract: A gain switching determination circuit (250) compares/determines a comparative input voltage (Vc) from an inter-stage buffer (230) with a first hysteresis characteristic, and outputs a gain switching signal (SEL) based on the comparison/determination result to first and second transimpedance amplifier core circuits (210, 220), thereby switching the gains of the core circuits. This obviates holding a comparison input voltage with long response time in a level holding circuit for gain switching determination, which allows instantaneous gain switching determination and instantaneous response corresponding to burst data.