Codex Corporation

Windata, Inc.

Alexander Herman

Colin Lanzl

Dan Budin

Robert L Smith, Jr

Daniel C Scavezze

Murray H Bolt

A local area network including at least one hub unit, at least one associated station unit and a wireless communication link between each hub unit and its associated station units. The communication link includes a wireless down-link channel for transferring information from each hub unit to its associated station units and a wireless up-link channel for transferring information from each station unit to its associated hub unit. Communication is conducted in accordance with a combination time division multiplexing and contention based protocol. A synchronized common slotted time frame between each hub unit and its associated station units is imposed by the hub unit.

Wireless local area network communications system

A data communication networking system for carrying messages among a plurality of data handling devices in accordance with a plurality of different networking modes, each device being compatible with at least one of the networking modes, the networking system including networking circuitry for interconnecting the devices effectively in accordance with different ones of the networking modes, and concentrator circuitry having control circuitry for providing signals indicative of the networking modes with which different devices are compatible, and routing circuitry responsive to the control circuitry for routing messages between a given device and the networking circuitry in accordance with one of the networking modes with which the given device is compatible.

Networking circuitry

A technique for regulating the transmission of messages initiated simultaneously by a plurality of nodes of a network, in which clock intervals are established for the network, a sequence of digital values is included in each message and is transmitted to the medium at the rate of one digital value per clock interval, the sequences included in messages that are initiated at the same time by more than one node are transmitted in the same sequence of clock intervals, the presence on the medium of a selected digital value during any clock interval in which a node is transmitting a different digital value within the sequence of a message is detected, and the transmission of the message is interrupted by the node upon such detection, without corrupting another node's transmission.

Network collision detection and avoidance apparatus

A data communication network over which data handling devices can transmit and receive packets among themselves having a bus, a number of subnetworks (each having interfaces for connecting a number of devices to each subnetwork), a concentrator for connecting each interface to the bus, each concentrator having a transceiver for transmitting, to the bus and to devices connected to each subnetwork, packets originating from devices within a subnetwork (transmitted packets), and for receiving from the bus packets originating from other subnetworks (received packets), collision avoidance circuitry for monitoring transmission attempts by devices connected to the subnetwork, for detecting competing transmission attempts that would create a collision on the subnetwork, and, upon such detection, permitting a selected attempt to enter the subnetwork, while preventing other attempts from entering it, collision detection circuitry for monitoring the bus and preventing all attempted transmissions from entering the bus whenever a packet from another subnetwork is present on the bus. In another aspect the interface means and the concentrator means include a network interface unit and a further interface unit.

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Sharon, MA, United States of America

Alexander Herman