A switching network for selectively connecting at least one input time-division channel on an input link (IL) to at least one output time-division channel on an output link (OL). The network is organized around a closed-loop link (10) on which circulates a multiplex message carrying 512 time-division exchange channels. The input and output links (LE and LS) are respectively multiplexed onto an input multiplex link (IML) and an output multiplex link (OML) which are coupled to the closed loop (10)...

A method and system is described for handling digital information in the form of addressed messages. The system includes a master communication loop such as a transmission cable. A plurality of sub-loops as well as devices are connected to the master loop through suitable interface units and sub-loop control units. In each of the sub-loops a plurality of devices capable of transmitting and receiving digitally coded messages are connected to the sub-loops through interface units. Two special char...

A data transmission arrangement comprising a plurality of data transmission loops wherein pairs of data transmission loops are interconnected by an interloop communication terminal. An interloop communication terminal comprises means for monitoring messages received on one loop of the pair to which it is connected to determine if the individual messages received are destined for the second loop of the pair and further comprises means for monitoring messages received on the second loop of the pai...

A digital communication loop system is disclosed wherein transfers of signal message blocks between intersecting loops are only made when a Hamming distance criterion is satisfied. More particularly, a decision to switch from one loop to another interconnecting loop is made when the Hamming distance between the interconnecting loop address and the final destination loop address is less than the Hamming distance between the loop address in which the message block currently resides and the final d...

An interactive information retrieval system is disclosed in which a large number of user terminals interact bilaterally with a centralized computer controlled data base by using a communications controller. In order to speed up the response time of the system, long messages from the controller to the terminal are broken into two segments, one segment just sufficiently long to engage the attention of the user while the balance of the message is being transmitted and verified. The balance of the l...

A communications system includes one or more channels each comprising a plurality of LANs having multiple stations. The LANs of a particular channel are interconnected by a bridge interface, the respective bridge interfaces being connected by a backbone network. Each station is capable of transmitting a data packet including a header having either a 0 or 1 bridge flag, LAN stations being responsive only to data packets having a 0 bridge flag and bridge interfaces only to packets having a 1 bridg...

A communications network comprising a hierarchy of communications systems all operating within the constraints of token ring protocols and operationally defining a single shared token ring. At least one of said systems is formed by a token ring hub as disclosed and claimed in our copending application 177,764 and is connected into a system comprising the next higher hierarchal level which may be another such token ring hub or a token ring LAN system. Each said hub has means for receiving a signa...

The present invention relates to an address filter method and unit to be used in a bridge unit or the like for connecting networks. The address filter unit carries out an address filter processing between a plurality of networks by using address information extracted from an incoming information frame registered in an entry table. In order to improve the processing efficiency of the address filter processing, the address filter unit includes timers corresponding to each address information regis...

A switch is provided for selectively routing digital information packets received from at least first and second external sources to at least first and second external destinations. At least one of the first sources generates an information packet including a datum, or a request therefore, and a corresponding descriptor. First and second routing interconnects have inputs for receiving packets from respective sources and outputs for transmitting packets to respective destinations. The interconnec...

There is disclosed an office communication system adapted to handle both bursty and continuous data transmission over a single transmission facility to a central switching network. A programmable station controller is used at each station location to interface a number of transmission inputs to the single communication link. The programmable station controller is arranged to statistically multiplex the inputs associated with the bursty data while allowing the continuous data to pass on dedicate ...