Abstract: An LAN system provided with a host system connected to an LAN through a plurality of LAN adapters, and a plurality of terminal systems for communicating with the host system through the LAN. A plurality of logical addresses for the host system are set correspondingly to physical addresses of the LAN adapters. One of the logical addresses is selected arbitrarily as a key (common) logical address. When the host system is to send a message to one of the terminal systems, the host system sets the key logical address of the host system as a source logical address included in the message, selects one of the LAN adapters and sends the message to the LAN through the selected LAN adapter.

Abstract: In a communication system having a plurality of host computers and two communication control processors (CCPs) connected to the respective host computers, one CCP is used as a regular CCP and the other CCP as a backup CCP. Each host computer establishes links with the two CCPs. Each of the host computers has a link flag for each link connected to each of the CCPs. The flag is set when the link is connected to the regular CCP. When the master host computer detects failure of the regular CCP, the master host computer sends an activate node request to the backup CCP to indicate that the backup CCP should be activated. Upon reception of the activate node request, the backup CCP sends a change output link request to all of the host computers. Upon reception of the change output link request, each of the host computers sets the link flag corresponding to the backup CCP to deal with the backup CCP as a regular CCP.

Abstract: A method for use in a network having a plurality of host computers, at least one communication control processor (CCP) commonly connected to the host computers, and a plurality of resources connected to the CCP. According to the method, if a resource is to be added to or deleted from the network, an operator designates a reconfiguration directory including at least one reconfiguration designating data for defining a relation between the network and a resource to be changed. Each host computer is assigned a reconfiguration command. In response to this reconfiguration command, each host computer reconfigures its own network configuration definition information in accordance with the defined reconfiguration designating data within the designated reconfiguration directory.

Abstract: A base-band and broad-band coexisting communication system comprises a transmission path, a plurality of first data terminal units outputting data to be transmitted in the form of pulse signals (base band signals), a plurality of second data terminal units for outputting data to be transmitted in the form of modulated signals (broad band signals) each having a center frequency within a predetermined frequency range, and a plurality of low-pass filters, each connected to each of the first data transmission units, for cutting off high frequency components of the base band signal outputted by the first data terminal device at a predetermined cut-off frequency which does not overlap with the broad band signals.

Abstract: There is a communication system comprising: an integrated services digital network (ISDN) having a plurality of information channels (Bch) and at least one control channel (Dch); a CPU (host computer) connected to said ISDN through a communication control processor (CCP); and a plurality of packet terminals connected to the ISDN. In the communication system, when a call request from the CPU or an incoming call request from one of the packet terminals is input to the CCP, if the B channel data link connection or the D channel data link connection for the packets has already been established between the CCP and the ISDN, the CCP selects the channel data link connection as a channel for communication with the packet terminal and multiplexes a plurality of calls to the same channel even if the other space B channels exist.

Abstract: In a loop transmission system utilizing specific patterns, a specified station for sending the specific patterns sends a specific pattern S or a specific frame S' which is not delayed in each station in advance of sending a specific pattern G used for data exchanging in each station, thereby ensuring rapid detection of abnormality of the specific pattern G.