Abstract: The present invention provides a method and apparatus for accurate packet time stamping in a network. The apparatus includes a time stamping logic, where the time stamping logic detects when a packet is transmitted or received; and a time source, where time information from the time source is latched when the time stamping logic detects the packet. In the preferred embodiment, the time stamping logic monitors packet traffic on a bus. When the time stamping logic detects a packet, a time stamping signal is generated which latches time information from the time source. The time information may then be used to measure the transmission delay for the packet for synchronizing the clocks at the transmitting and receiving nodes.

Abstract: The present invention provides a method and apparatus for alternating current (AC) power failure detection. The method includes amplifying an AC power waveform, where the amplified waveform is asserted when the AC power waveform is in a vicinity of a zerocrossing and negated at all other times; initiating a counter when the amplified waveform is asserted; and determining if the counter equals or exceeds a reference number, where the counter being equal or exceeding the reference number indicates an AC power failure. The present invention converts an AC power signal to a near digital signal, where the near digital signal is asserted when the AC power signal is in the vicinity of a zero-crossing and negated at all other times. When the near digital signal is asserted, a counter in a controller begins counting, and ends the counting when the near digital signal is negated.

Abstract: The present invention provides a method and system for data transmission in a computer network. The method includes sending data with a first structure to a connector, the connector coupled between the front-end and the back-end, the data being either from the front-end or the back-end; and mapping the data to a second structure by the connector, such that a change in a configuration of at least one control point at the back-end is transparent to the front-end. In the preferred, the method includes an additional device, a connector, that serves as a gateway between the enterprise and the control network. The enterprise defines structures, data points, that it prefers to use and configures the gateway to use them. From then on, communication between the enterprise and the connector uses those structures. The enterprise also configures the gateway to communicate with the desired elements of the control network by defining input/output points.

Abstract: The present invention provides a method for reliable stale packet recognition in a network. The method includes: rewriting a packet's transaction identifier (TID) such that the rewritten TID is not a same TID as a previous transaction if the packet could be erroneously seen as a duplicate packet by the receiving router; sending the packet to the receiving router; and blocking the sent packet from transmission to the receiving node if a transaction timer has expired and if the sent packet's TID is the same TID as the previous transaction. The method blocks duplicate packets which arrive at the receiving router after the expiration of the transaction timer. When a packet for a new transaction to be sent to the receiving node is assigned the same TID as the previous transaction, the sending router rewrites the packet's TID to avoid the erroneous recognition of this packet as a duplicate by the receiving router.