Abstract: A distributed control system architecture (HSE) provides an open, interoperable solution optimized for integration of distributed control systems and other control devices in a high performance backbone, provides an open, interoperable solution that provides system time synchronization suitable for distributed control applications operable over a high performance backbone, and provides an open, interoperable solution that provides a fault tolerant high performance backbone as well as fault tolerant devices that are connected to the backbone. The distributed control system architecture comprises a High speed Ethernet Field Device Access (HSE FDA) Agent, which maps services of a distributed control system, e.g., a fieldbus System, to and from a standard, commercial off-the-shelf (COTS) Ethernet/Internet component. The distributed control system architecture also comprises a High speed Ethernet System Management Kernel (HSE SMK) that operates to keep a local time, and keeps the difference between the local time and a system time provided by a time server within a value specified by the time sync class. The local time is used to time stamp events so that event messages from devices may be correlated across the system. The distributed control system architecture further comprises a High speed Ethernet Local Area Network Redundancy Entity (HSE LRE) that provides redundancy transparent to the applications running on the system. The HSE LRE of each device periodically transmits a diagnostic message representing its view of the network to the other Devices on the system. Each device uses the diagnostic messages to maintain a Network Status Table (NST), which is used for fault detection and selection from a redundant pair of resources.

Abstract: A method and apparatus for synchronizing a clock by means of a wireless communication link is herein disclosed. At least one system client accesses at least one time reference server via a wireless communications link. The time reference server comprises, at a minimum, a clock reference, a processor and a wireless communication adapter. Each client comprises, at a minimum, a settable clock, a processor and a wireless communication adapter. In one embodiment of the invention, the time reference is sent from the time server to a client in response to a request from the client. In another embodiment, the time reference is sent from the time server to a client at predetermined times, without the need for a request from the client. Thus, in such an embodiment, the time server is able to locate clients automatically over the wireless communications link. In yet another embodiment of the invention, a client may select which of a plurality of time reference servers to access in order to receive time reference information.

Abstract: RFC 1589 describes a UNIX kernel implementation model for high- precision time-keeping. This model is meant for use in conjunction with the Network Time Protocol (NTP, RFC 1305), or similar time synchronization protocols. One aspect of this model is an accurate interface to the high-accuracy, one pulse-per-second (PPS) output typically available from precise time sources (such as a GPS or GOES receiver). RFC 1589 did not define an API for managing the PPS facility, leaving implementors without a portable means for using PPS sources. This document specifies such an API.

Abstract: An enhanced interactive television broadcast is disclosed wherein an audio/video broadcast is viewed on a first display system, and an “enhancement” to the broadcast is simultaneously viewed or experienced on a second, separate display system. The “enhancement” is synchronized to the broadcast, and delivered to a user as a code fragments, such as a JavaScript message. URLs are not required. Portions or elements of a web page are reduced to single code fragments, rendered client-side upon receipt. The invention implements Network Time Protocol (NTP) to synchronize the client's application clock to global time. Messages, or JavaScript code fragments, are time-stamped and evaluated based on the client's application clock.

Abstract: : Although Coordinated Universal Time (UTC) is the time scale that is transmitted by almost all time services, this scale is awkward to use in the vicinity of a leap second Many computer systems cannot represent the epoch corresponding to a positive leap second (23:59:60), and remain synchronized to UTC by stopping the clock at 23:59:59 for 1 extra second whenever a leap second is to be added This makes it impossible to assign unambiguous ante tags to events that happen during this period In addition, computing the length of a time interval that includes a leap second of either sign is difficult because simply subtracting the two UTC time stamps at die end-points of the interval does not account for the time interval occupied by the leap second itself To address these issues, we have augmented the Network Time Protocol to allow a client system to reconstruct TAI from UTC and a table of leap seconds This time scale has no discontinuity during the leap second Intervals computed using TAI are unaffected by the additional time occupied by the UTC leap second, and the TAI time scale provides an unambiguous time tag to any event -- even one that happens during a UTC leap second Although our solution is unique to servers that support the Network Time Protocol, it could be adapted to other time services and formats Such systems could support time tags using either UTC or TAI, and would significantly reduce the problems that result from using UTC alone

Abstract: PROBLEM TO BE SOLVED: To provide a high precision delay measurement equal to or less than the unit of milliseconds suitable for a measuring method or the like to which high precision is required for measuring delay time in a distributed computer network environment or the like. SOLUTION: A time source S is acquired from a time server 101, a frame synchronizing signal FS is detected from a synchronous media 102, time is managed by using them, a time stamp generated on the basis of this managed time is distributed to the transmitting side and receiving side of an asynchronous transmission network, a packet P containing a time stamp TS1 distributed to the transmitting side is transferred through the asynchronous transmission network to the receiving side, the time stamp is extracted from this packet, the difference between this extracted time stamp and a time stamp TS2 distributed to the receiving side is calculated and the transmission delay time of the network is measured from this difference.

Abstract: PROBLEM TO BE SOLVED: To provide a time synchronizing system in a communication network which can reduce a load of an NTP server. SOLUTION: A representative terminal out of terminals connected on a LAN inquires an NTP server of a time and notifies other terminals of acquisition information in a circular form. Also, time information circulation is preferably regularly performed and, moreover, a cyclic interval is determined by recording and analyzing a correction value of time information correction regularly executed.

Abstract: PROBLEM TO BE SOLVED: To hold time information of an incorporated clock means to an appropriate value and to execute various controls by connecting a system to a prescribed terminal connected to a local area network through the use of a prescribed ntp protocol in an initialization and registering an acquired present time information in the clock means of a self-terminal. SOLUTION: A network facsimile equipment (FX) executes a transmission function with work stations WS1-n, a router device RT and a mail server device SM through a local area network LAN. FX can execute picture communication with other FX through a public network PSTN and a host mail server device SM acquires present time information by using a prescribed ntp protocol at a prescribed time interval in an initialization processing. FX registers/sets present time information in the clock means of a self-device. Thus, present time information outputted from the clock means becomes a precise value and FX can execute an operation, based on appropriate time.