Abstract: A trainable transceiver for learning and transmitting an activation signal that includes a rolling or other variable code for remotely actuating a device, such as a garage door opener. The trainable transceiver preferably includes a receiver, a signal generator, and a controller operating in a learning mode or in an operating mode. In the learning mode the controller recognizes the presence of a variable code, identifies a prestored cryptographic algorithm related to the cryptographic algorithm used by the remote transmitter to generate the variable code, and stores data identifying the cryptographic algorithm and last transmitted code of the activation signal. In the operating mode, the controller generates output data representing a next sequential code of the variable code using the identified cryptographic algorithm and the data representing the last transmitted code.

Abstract: A trainable transceiver provides an integrated trainable transmitter and control system receiver for a vehicle electrical system. The transceiver includes an input circuit and an output circuit coupled to a controller. The transceiver also includes an interface connected between the controller and the vehicle's electrical system. The input circuit which receives RF signals includes an amplitude control for adjusting the reception range of the transceiver. The transceiver also disconnects the output circuit from the antenna in a remote control training mode or a transmitter signal detection mode. The transceiver is manually controlled to enter the remote control training mode and a transmission mode for controlling a remote device. The transceiver automatically enters the transmitter signal detection mode on a periodic basis.

Abstract: A trainable transceiver provides an integrated trainable transmitter and control system receiver for a vehicle electrical system. The transceiver includes an input circuit and an output circuit coupled to a controller. The transceiver also includes an interface connected between the controller and the vehicle's electrical system. The input circuit which receives RF signals includes an amplitude control for adjusting the reception range of the transceiver. The transceiver also disconnects the output circuit from the antenna in a remote control training mode or a transmitter signal detection mode. The transceiver is manually controlled to enter the remote control training mode and a transmission mode for controlling a remote device. The transceiver automatically enters the transmitter signal detection mode on a periodic basis.

Abstract: A trainable transceiver provides an integrated trainable transmitter and control system receiver for a vehicle electrical system. The transceiver includes an input circuit and an output circuit coupled to a controller. The transceiver also includes an interface connected between the controller and the vehicle's electrical system. The input circuit which receives RF signals includes an amplitude control for adjusting the reception range of the transceiver. The transceiver also disconnects the output circuit from the antenna in a remote control training mode or a transmitter signal detection mode. The transceiver is manually controlled to enter the remote control training mode and a transmission mode for controlling a remote device. The transceiver automatically enters the transmitter signal detection mode on a periodic basis.

Abstract: A vehicle accessory includes a trainable transmitter for duplicating the signal of an existing remote control. In one embodiment, the system includes a variable frequency generator having a frequency control input and an output. In one embodiment, also, the transmitter includes a switch for selectively disabling the variable frequency generator. According to another embodiment, the transmitter is trained by adjusting the frequency of the signal output by the variable frequency generator until it matches a signal transmitted by an existing remote control for a garage door opening mechanism. According to another embodiment, a variable attenuator is controlled to adjust the magnitude of the output signal of the variable frequency generator in inverse relationship to the duty cycle of output signals therefrom.

Abstract: A vehicle accessory includes a trainable transmitter for duplicating the signal of an existing remote control. In one embodiment, the system includes a variable frequency generator having a frequency control input and an output. In one embodiment, also, the transmitter includes a switch for selectively disabling the variable frequency generator. According to another embodiment, the transmitter is trained by adjusting the frequency of the signal output by the variable frequency generator until it matches a signal transmitted by an existing remote control for a garage door opening mechanism. According to another embodiment, a variable attenuator is controlled to adjust the magnitude of the output signal of the variable frequency generator in inverse relationship to the duty cycle of output signals therefrom.

Abstract: A transmitter includes an attenuator for adjusting the level of an output signal as a function of the pulse width and frequency of the output signal. The transmitter also includes receiver components which are disabled when the transmitter is transmitting.