Abstract: An improved apparatus and method for communicating information in a networked system wherein network variables are employed to accomplish such communication. Network variables allow for standardized communication of data between nodes in a network. A first node may be programmed, for example, to sense certain information and to report the information as a network variable X. A second node may be programmed to receive the variable X and to control devices based on the current value of the variable. The present invention provides for defining connections between the first and second node to facilitate such communication and for determining addressing information to allow for addressing of messages, including updates to the value of the variable X, between the nodes.

Abstract: A data communications network for delivering power and communications over the same cable bundle includes a plurality of communications nodes wherein associated with each of the nodes is a transformer having a core, a primary winding and a secondary winding. The secondary winding has a centertap connection which either splits or merges the current in the secondary winding to eliminate net DC flux within the transformer. A DC/DC converter is also included for transforming the relatively high DC voltage of the cable down to a regulated supply potential for use by that node. The converter is coupled between the centertap of the transformer and the cable bundle. A power source provides the DC voltage distributed across the network and is coupled to the cable bundle via a centertap connection of another winding.

Abstract: An improved correlator for use in a spread spectrum communications system which operates with a predetermined chip sequence includes an N-stage correlation register, wherein each stage corresponds to a signal chip in the sequence, an a means for autocorrelating each of the N stages with the corresponding chips in the sequence. The correlator further includes a means for modifying the sequence to accomodate multiple communication channels.

Abstract: A transceiver for transmitting and receiving digital data is disclosed. The transceiver employs direct sequence spread spectrum communications techniques for reducing interference among multiple users in a communications network environment. Each transceiver has a transmitter for locking a digital bit stream to a predetermined spread spectrum chip sequence and carrier signal. Frequency of the carrier signal and the chip sequence. Both the carrier signal, the chip sequence and the bit stream rate are derived from an integrally related to an accurate reference frequency to facilitate rapid acquisition and decoding of the signal by another transceiver. To provide for multiple communications channels on a single transmission medium, means for producing selectable carrier frequencies and/or selectable spreading sequences are included.

Abstract: A network for sensing, communicating and controlling where a plurality of cells communicate with one another through packets. When a cell receives a packet, it determines the baud rate of the received packet and stores this rate. In replying to the packet a cell uses a backoff algorithm to determine how many slots it must wait before replying. The duration of these slots is determined based upon the stored baud rate.

Abstract: A transceiver for transmitting and receiving digital data is disclosed. The transceiver employs direct sequence spread spectrum communications techniques for reducing interference among multiple users in a communications network environment. Each transceiver has a transmitter for locking a digital bit stream to a predetermined spread spectrum chip sequence and carrier signal. Frequency of the carrier signal and the chip sequence. Both the carrier signal, the chip sequence and the bit stream rate are derived from an integrally related to an accurate reference frequency to facilitate rapid acquisition and decoding of the signal by another transceiver. The transceiver also has a receiver portion for acquiring and decoding a transmitted and direct sequence spread spectrum signal to recover the digital bit stream using the spread spectrum chip sequence and carrier signal.

Abstract: A network for sensing, communicating and controlling employing a plurality of cells which communicate through packets. First cells are assigned an announcer function, others a listener function with at least one announcer or listener cell also performing the function of repeating at least some of the packets. The cells are organized into groups, each group being assigned a group function. Group identification numbers are included in the packets to allow the cells for a particular group to identify packets intended for it.

Abstract: A network for sensing, controlling and communicating information. The network comprises a plurality of cells including a first cell for sending a packet of information, a second cell for receiving the packet of information and a plurality of repeater cells for repeating the packet prior to its arrival at the second cell. A method is described including the steps of generating a random number and including the random number in the packet; performing a calculation by the repeater cells of fields including the random number to generate a first number; storing the first number; performing a calculation on subsequent packets received by the repeater cells to provide a second number; comparing the second number to the first number; and rebroadcasting the subsequently received packet if the second number is different than the first number.

Abstract: A network for sensing, communicating and controlling where a plurality of cells communicate in the network through packets. A first cell transmits a sequence number and a retransmit flag with the messages. The messages are acknowledged by a second cell if the sequence number is different that the previously received sequence number. If the sequence number is the same, the second cell acknowledges the message only if the retransmit flag indicates the message is being retransmitted by the first cell. The second cell takes action on the message only if the sequence number is different than the previously received sequence number.

Abstract: A network for sensing, communicating and controlling, which uses packets to communicate between a plurality of cells. Cells in a system are given a system identification number (e.g., a 48 bit number). One part of the system identification number (e.g., 32 bits) is transmitted with a packet. The remaining part of this system identification number (e.g., 16 bits) is included in the computation of a cyclic redundancy code (CRC). A receiving cell is able to verify that a packet is intended for it by examining the first part of the system identification number in the packet and by computing and comparing the CRC in the same manner as was done by the transmitting cell.