Abstract: A powerline communication system comprises a master and slave configuration in which the master provides both operating power and control commands to the slave over a single pair of wires. The slave, in turn, is able to communicate its status to the master with a return communications channel on the same pair of wires. Each sender impresses its signals on the power lines with an isolation transformer coupled to the gate of a power MOSFET transistor that shunts the power lines. Each receiver samples the signals from the sender with an isolation transformer that has its primary winding placed in series with the power lines. The master initiates a synchronizing pulse and places data in various timeslots. The slave follows with an initiating sync pulse followed by data in a group of timeslots. Edge-detection, rather than level-detection is used at the receivers for added immunity to supply and load changes. A double-pulse sync is used for special time slot reporting.

Abstract: In a system in which a power supply provides power to a plurality of remote devices and sensoring devices, apparatus for applying an initial control signal to the power source lines activates a clock/logic network associated with each group of remote sensoring devices and load devices. The initial control signal defines and synchronizes a plurality of time intervals following the initial control signal. A sensor associated with a clock/logic apparatus can apply a signal to the power line during a time interval that can be interpreted by the control apparatus as an indication of a state of the associated sensor. Similarly, the clock/logic apparatus can enable a load element during a pre-established time interval following the initial control signal, however, the load element can be activated only if the control apparatus applies a signal to the power lines during the pre-established period.

Abstract: An electronic digital combination lock including a frame supported within the interior of a door; a bolt mechanism which moves in relation to the frame to be retracted from a door jamb to open the door; a logic circuit which generates a control signal in response to entry of a predetermined combination signal, including push button switches which are housed within the door interior and produce bits when selectively depressed; and, a rotatable handle member which is coupled to the frame from the outside surface of the door to activate the bolt mechanism, including a tube that is coupled adjacent the push button switches and is selectively rotatable to depress each of the switches to generate the predetermined combination signal. The handle member including the tube has only limited rotational movement until the correct combination signal is entered, at which time an electromagnetic and lever mechanism is energized to release the handle member for extended rotation to retract the bolt mechanism.

Abstract: An electronic digital combination lock including a frame supported within the interior of a door; a bolt mechanism which moves in relation to the frame to be retracted from a door jamb to open the door; a logic circuit which generates a control signal in response to entry of a predetermined combination signal, including push button switches which are housed within the door interior and produce bits when selectively depressed; and, a rotatable handle member which is coupled to the frame from the outside surface of the door to activate the bolt mechanism, including a tube that is coupled adjacent the push button switches and is selectively rotatable to depress each of the switches to generate the predetermined combination signal. The handle member including the tube has only limited rotational movement until the correct combination signal is entered, at which time an electromagnetic and lever mechanism is energized to release the handle member for extended rotation to retract the belt mechanism.