摘要:
A remote line monitoring device and method for a CATV system in which a center facility is connected to plural terminal units through cables of the system to transmit television signals to subscribers' homes. A plurality of monitoring terminal units are provided along various points of the interconnecting cables. Each of the monitoring terminal units is identified by an unique address. To determine conditions throughout the system, a central monitoring system transmits polling signals on the cables. If an address contained within the polling signals matches with a prestored identifying address, a monitoring terminal unit responds by transmitting data produced by monitoring converter units back to the center facility. The center facility can then display the data or produce indications identifying problems along the cables.
摘要:
A bidirectional data communications system having many remote terminals operating with a central unit includes means at each terminal for reproducing a clock from the incoming data. Upstream data from the terminals to the central unit is transmitted at the same frequency as the incoming data using the reproduced clock from the downstream transmission. At the central unit, the incoming data from each terminal is of arbitrary phase, but must be extracted without delay from the upstream transmission for data processing purposes. A clock signal substantially resynchronized with the data stream is provided by detecting the initial presence of data, and timing the frequency division of a higher frequency original clock so that the phase and frequency of the data match the clock requirements at the central unit.
摘要:
In a power supply control apparatus for controlling turn-on/turn-off of power of a main power supply to a load via a switch section, a drive signal producing section produces a drive signal for controlling ON/OFF operations of the switch section, based on an activation signal output from an activating section. A standby power supply supplies operation power to the activating section 11 and the drive signal producing section. A power failure monitoring section produces an energization signal indicative of a result of monitoring of an output of the main power supply, and outputs the signal to the activating section. The activating section outputs the activation signal based on the energization signal.
摘要:
The CATV system includes a center device and a plurality of terminal devices. The center device sends downstream timeslots, to the terminal devices, including upstream timeslots occupancy information and collision information. Upstream timeslot occupancy information indicates whether or not an upstream timeslot corresponding to the downstream timeslot is vacant, and collision information indicates whether or not a collision has occurred. The terminal device receives the downstream timeslot, checks upstream timeslot occupancy information to detect upstream timeslot in the vacant state, and sends upstream data to the center device via the vacant upstream timeslot. If the upstream timeslot makes a collision, the center device detects it and sends a downstream timeslot which includes collision information indicative of the occurrence of the collision. The user of the terminal device recognizes the collision having occurred or not by referring to the collision information.
摘要:
The CATV system includes a center device and a plurality of terminal devices. The center device sends downstream timeslots, to the terminal devices, including upstream timeslot occupancy information and collision information. Upstream timeslot occupancy information indicates whether or not an upstream timeslot corresponding to the downstream timeslot is vacant, and collision information indicates whether or not a collision has occurred. The terminal device receives the downstream timeslot, checks upstream timeslot occupancy information to detect upstream timeslot in the vacant state, and sends upstream data to the center device via the vacant upstream timeslot. If the upstream timeslot makes a collision, the center device detects it and sends a downstream timeslot which includes collision information indicative of the occurrence of the collision. The user of the terminal device recognizes the collision having occurred or not by referring to the collision information.
摘要:
A remote control system for an audio/video system has a first remote controller for transmitting a first remote control signal for designating and operating one of the A/V devices. In accordance with the first remote control signal, an operational mode for a designated A/V device is set. A second remote control signal transmitter is provided for transmitting a second remote control signal for operating the designated A/V device in accordance with the set operational mode.
摘要:
A memory system including a circuit for switching control of a read-only memory and a random-access memory to allocate addresses thereto. The addresses are switched between the read-only memory and the random-access memory by selecting a mode in which the read-only memory is operated when reading therefrom and the random-access memory is operated when writing thereinto, and a mode in which the random-access memory is operated when reading therefrom and writing thereinto.
摘要:
In a cable television system wherein a polling channel is provided for two-way communications between the center and the terminal units, video data signals are transmitted on request from the center to the terminal units during an otherwise idle period in said polling channel.