A remote time clock unit is connected as a part of one remote station of several in a data communication system having a controller to generate message frames for reading and resetting of the clock. The clock unit is a digital type having individual day, hour, minute and second counters, with binary coded decimal paralleled input and outputs connected for direct transfer of the input setting to the outputs. The clock outputs, through the loop controller, actuate time operated loads at loop remotes in response to programs at the loop controller. The clock unit is connected to the system by a module address decoder and a command decoder to read the message frames and provide for setting of the day, hour and minute counters. The clock unit is read by message frames with a pair of succeeding frames reading the three BCD bits for the day while simultaneously reading the hour data and the minutes or seconds data. The system is automatically updated each minute or second by an interrupt signal device connected to the input of the minute and second counters. The interrupt device normally connects the minute selection to control updating, but is connected to the system for response to a message frame signal to select the second interrupt interval.
A digital display system with a control unit and a plurality of display units each adapted to be driven by a signal from the control unit. The control unit includes an A.C. power supply for generating a fixed A.C. voltage, and the control unit produces a multi-parallel-bit digital signal indicative of time or the like, extracts a pulse signal at the fixed frequency from the A.C. voltage, modulates the pulse signal with respective bits of the digital signal to produce a time-division multiplex signal, supplies the A.C. voltage to the respective display units and feed the time-division multiplex signal. Each of the display units rectifies the supplied A.C. voltage to produce a power supply voltage for the display unit, produces from the supplied A.C. voltage to be used for display, further produces a display signal from the produced A.C. voltage and the time-division multiplex signal and feed the display signal to a display device to display time or the like. The time-division multiplex signal sent from the control unit includes a reference time signal of a fixed frequency necessary for the display units so that the display units do not need to include oscillators to produce the reference time signal.
A clock synchronized by date and time information taken from Caller ID information packets delivered with incoming calls on a telephone line provided with Caller ID service.
A packet switching system in which a remote real-time clock is accurately synchronized to a standard real-time clock via X.25 (CCITT) controlled high-speed transmission links. Synchronization is achieved by the transmission of an interrupt packet and a data packet between a remote processor controlling the remote real-time clock and an administrative processor controlling the standard real-time clock. Synchronization involves the following steps: (1) assembling an interrupt packet comprising the least significant bits of the remote real-time clock for transmission to the administrative processor by the remote processor, (2) calculating bits representing the difference between the transmitted least significant bits of the remote real-time clock and the least significant bits of the standard real-time clock by the administrative processor, (3) assembling a data packet comprising bits representing the state of the standard real-time clock and the difference bits for transmission to the remote processor by the administrative processor, (4) adding the difference bits to the bits representing the state of the remote real-time clock by the remote processor, and (5) adding a predefined value to the most significant bits of the remote real-time clock by the remote processor if the transmitted least significant bits of the standard real-time clock are numerically greater than the least significant bits of the remote real-time clock.
Digital display devices and digital timepieces in which the display is remotely updated. The method permits continuous updating with simple and inexpensive TTL Logic and less frequent updating with microprocessor means. The remote updating signal can be transmitted through telephone means, broadcast means or other standard communications means to simultaneously update multiple digital displays. A single improved digital display device can be utilized as a master for controlling the display of multiple devices.
An electronic apparatus particularly suitable for processing, memorizing, utilizing and returning electrical signals and coded messages, includes essentially two sections (A, B), the first (A) constituting a self-contained, self-powered information unit provided with circuits for the wired or wireless reception of coded messages, decoding circuits for said messages, and monitoring circuits and/or circuits for automatically checking correct operation, the second (B) constituted essentially by a plurality of different units (B1, B2, B3, B4) to which, singularly and/or simultaneously, the first section (A) can be connected for the transfer, processing, recording and utilization of the signals provided by said section (A) in relation to the specific function to be performed, and for the deactivation of said section (A).
