Abstract: A trainable transceiver for learning and transmitting an activation signal that includes an RF carrier frequency modulated with a code for remotely actuating a device, such as a garage door opener. The trainable transceiver preferably includes a controller, a signal generator, and a dynamically tunable antenna having a variable impedance that may be selectively controlled in accordance with a detector circuit signal. The detector circuit provides a measurement of the transmission power and is also used to vary the applied transmission power of the transceiver in response to operating and environmental parameters.

Abstract: A wireless control system for customizing a wireless control signal for a remote electronic system based on the location of the wireless control system includes a transmitter circuit, an interface circuit, and a control circuit. The transmitter circuit is configured to transmit a wireless control signal having control data which will control the remote electronic system. The interface circuit is configured to receive navigation data from a navigation data source. The control circuit is configured to receive a transmit command, to receive navigation data, to determine a current location based on the navigation data, and to command the transmitter circuit to transmit a wireless control signal associated with the current location.

Abstract: A trainable transmitter comprises a receiver, a signal generator, and a processor. The receiver receives a signal from a transmitter. The signal generator generates a signal having a frequency related to a frequency control signal supplied to a frequency control terminal of the signal generator. The processor is directly coupled to the frequency control terminal of the signal generator for supplying the frequency control signal and directly coupled to an output terminal of the signal generator for monitoring the frequency of the signal output from said signal generator.

Abstract: A transmitter for wirelessly controlling a plurality of remote electronic systems includes a memory, a transmitter circuit, and a control circuit. The memory is configured to store a plurality of control data messages, each control data message configured to control a different remote electronic system. The control circuit is configured to command the transmitter circuit to transmit a plurality of wireless control signals in response to a single event, each wireless control containing a different control data message.

Abstract: Data structures and methods, systems and computer program products for searching, inserting and/or deleting entries in a database which includes a hash value corresponding to data of the entry and which are stored in a hash-ordered sequence such that a linear search for an entry from an address corresponding to the hash value of the entry will result in the data being located by examining entries in consecutive addresses before an address without an entry is reached are provided. Such methods, systems, computer program products and data structures may be particularly useful for Internet Protocol Security (IPSec) security association databases (SADs).

Abstract: A control circuit comprises a plurality of amplifier and filter stages for detecting ignition noise present on the battery line of a vehicle. It applies the filtered and amplified ignition noise signal to a hysteresis latch circuit for providing a control output signal for a solid-state switch coupled between the vehicle battery conductor and a load. Such a circuit provides accurate detection of only ignition noise to provide operating power from a battery line to a circuit to be powered thereby and is immune from extraneous noise frequencies and voltage levels.

Abstract: A warning system automatically alerts a vehicle operator to the fact that the next available exit should be taken for a desired or necessary service such as refueling. The system includes a source of information providing the current vehicle location as well as a source of information identifying the location of available selected service locations closest to each of the next two exits of a limited access highway. The system in a preferred embodiment includes a source of information indicating the available range of the vehicle (distance to empty or D.T.E.) and a microprocessor for calculating when the driver should take the next available exit to reach the desired service. The system further includes a suitable alarm which may be an audible alarm, a visual alarm or both to alert the vehicle operator that the next available exit should be taken.