Abstract: A data communications transceiver for transmitting signals to and from a medium has an output driver connected to the medium through a series connected first pair of diodes and a receiving transistor amplifier whose input is connected to the medium and whose output leads are each connected to a separate one of a second pair of diodes, whereby a low input capacitance is achieved.

Abstract: A graphics input device for use with location indicating means to present graphic data upon a computer controlled visual display. The device includes a pen having a housing within which is disposed a conductive stylus shaft, one end extending beyond the housing to serve as the writing tip. A cylindrical off-axis pressure transducer encircles a portion of the stylus shaft within the housing, adjacent its writing end, for generating a variable output electrical signal proportional to the variable off-axis force applied to the stylus independently of the rotational orientation of the pen. A display processing and control system receives the variable signals and modifies a visual characteristic of the graphic data in response thereto.

Abstract: A data communications transceiver for transmitting signals to and from the communicating medium, with the transceiver including an input terminal, a short time constant differentiator connected to the input terminal to differentiate signals applied thereto, a Schmitt trigger supplied with the output of the short time constant differentiator for producing a corresponding square wave output signal, a first driver supplied with the square wave output of the Schmitt trigger for supplying it to the communicating means, amplifying means for receiving signals from the communicating medium and for producing an amplified output therefrom, a second short time constant differentiator supplied with the output of the amplifying means and for supplying it to a second Schmitt trigger for producing a corresponding second square wave signal, and a second driver supplied with a second square wave signal for supplying it to an output terminal.

Abstract: A data communications transceiver for transmitting signals to and from the communicating medium, with the transceiver including an input terminal, a short time constant differentiator connected to the input terminal to differentiate signals applied thereto, a Schmitt trigger supplied with the output of the short time constant differentiator for producing a corresponding square wave output signal, a first driver supplied with the square wave output of the Schmitt trigger for supplying it to the communicating means, amplifying means for receiving signals from the communicating medium and for producing an amplified output therefrom, a second .[.short time constant.]. differentiator supplied with the output of the amplifying means and for supplying it to a second Schmitt trigger for producing a corresponding second square wave signal, and a second driver supplied with a second square wave signal for supplying it to an output terminal.