Abstract: A semiconductor device that functions as a key to control access to a computer or a software program resident in a computer or provides for secure communications is disclosed. The device executes an algorithm that combines a root and a seed to produce a password. The password is input to the computer. The computer uses an equivalent algorithm to produce a password within the computer. Comparison or other methods are employed to allow access to the computer or computer program or to allow for secure communications. The computer can be coded to produce on a video display thereof a time-space stimulus pattern which can be received by sensors of the key. Alternatively, a keypad can be employed to input the stimulus output from the computer into the access key. Further the present system allows for secure communication using algorithms between different computers and between distant locations.

Abstract: A semiconductor device that functions as a key to control access to a software program resident in a computer. The device includes a continuously running pulse generator that produces an output representative of real time, a shift register permanently storing a unique number and circuitry for executing an algorithm that combines real time and the permanently stored unique number to produce a password. The password is input to the computer. The computer is coded to execute an equivalent algorithm to produce a password within the computer. The two passwords are compared and access to the computer program is afforded only if they bear a prescribed relationship. The computer can be coded to produce on the video display thereof a timespace pattern on the computer video display, circuitry for deriving the stimulus number therefrom, and circuitry for processing the stimulus number so that the password displayed by the key is a function of the value of the stimulus number.

Abstract: A semiconductor device that functions as a key to control access to a software program resident in a computer. The device includes a continuously running pulse generator that produces an output representative of real time, a shift register permanently storing a unique number and circuitry for executing an algorithm that combines real time and the permanently stored unique number to produce a password. The password is input to the computer. The computer is coded to execute an equivalent algorithm to produce a password within the computer. The two passwords are compared and access to the computer program is afforded only if they bear a prescribed relationship. The computer can be coded to produce on the video display thereof a time-space pattern on the computer video display, circuitry for deriving the stimulus number therefrom, and circuitry for processing the stimulus number so that the password displayed by the key is a function of the value of the stimulus number.

Abstract: Circuitry for affording access to a common passive bus by a plurality of computer devices connected to the bus. Each of the devices is provided with the circuitry, which operates in three sequential phases: a bus request phase, an address phase and a data transfer phase. Circuitry interconnecting the bus connections for permitting a device to initiate the bus request phase only if all devices superior to it are not in the bus request phase thereby establishing a priority ranking among the devices. The circuitry also includes a call back system wherein if a given device is unready to receive data when addressed by a source device, such device will, when it is ready, call back the source device that was previously and unsuccessfully attempting to transfer data to it.

Abstract: A transducer for placement in fixed relation to the axle/wheel assembly of a vehicle and adjacent to the body of the vehicle, the transducer cooperating with the vehicle body to form a reactance that has a magnitude proportional to the distance between the transducer and the vehicle body. The magnitude of the reactance thus varies in response to variations in distance between the vehicle body and the transducer when the body is caused to experience oscillation on the springs thereof. Such oscillation is damped by the vehicle shock absorbers. A capacitive transducer and an inductive transducer, both of which include a guard or shield which shields the transducer from ground. An oscillator circuit wherein the frequency of oscillation is determined by the above mentioned reactance, the oscillator circuit having a non-ground common to which the guard is connected.

Abstract: A transducer for placement in fixed relation to the axle/wheel assembly of a vehicle and adjacent to the body of the vehicle, the transducer including an antenna plate which in cooperation with the vehicle body forms a capacitance. The magnitude of the capacitance varies in response to variations in distance between the vehicle body and the antenna plate when the body is caused to experience oscillation on the springs thereof. Such oscillation is damped by the vehicle shock absorbers. The transducer includes a guard or shield which shields the antenna from significant capacitive reactance with respect to ground. An oscillator circuit wherein the frequency of oscillation is determined by the above mentioned capacitance, the oscillator circuit having a non-ground common to which the guard is connected.

Abstract: A test probe for effecting temporary electrical connection to circuit terminals of miniature integrated circuits or like elements with small inter-terminal spacings. The probe has an insulative tip having a cross-sectional dimension smaller than the space between adjacent terminals. In an axially extending groove in the tip is a stiff wire, and a mechanism is provided for controllably moving the wire out of the groove after the tip has been inserted between two terminals. When the wire moves out of the groove, it contacts one of the electric terminals and wedges the insulative tip against the adjacent terminal so as to retain the probe in place.