Abstract: A system is provided for communicating between terminal units joined on a power distribution network. The terminal units in the system are capable of interfacing with external devices to which they are attached, of communicating with other terminal units, and of functioning as repeater units. When a message is received by a terminal unit, it determines whether the message is intended for itself or for another terminal unit. If it is intended for another terminal unit, it amplifies and retransmits the message. The system also includes means for determining the shortest communication path between one unit and an intended recipient terminal unit. When a previously established communication route is no longer effective, the system automatically determines a new communication route.

Abstract: A thermal recording stylus comprised of a ceramic tip with two passages from openings near a frustum-shaped end to openings at the rear, an electrical heating element wrapped around the frustum-shaped end from one opening thereof to the other, and electrical power leads extending from the ends of the heating element through the passages. The leads and heating element are secured with cement in the passages, and the entire assembly is secured in a sleeve with cement and a ring wedged between a conical section of the ceramic tip and the sleeve.

Abstract: An improved device for capacitively detecting signals generated in a writing table by a grid of conductive wires that produce a varying electrostatic field near its surface to be picked up through a stack of paper with the table functioning as one plate of a capacitor, and a conductive stylus as the other plate. The improvement consists of grounding the stylus, which has an extended body portion surrounded by a tubular member, extending the tubular member to a point very near the stylus tip where it functions as the second plate of a capacitor, and connecting the tubular member to a preamplifier mounted in the device.

Abstract: An improved apparatus capable of converting the position of a pen-type sensor relative to the surface of a writing table into an electrical signal representative of such position and which may be utilized for control, data input or transmission purposes. The writing table includes two sets of independent, spaced-apart conducting wires which form a grid throughout the writing area. The conducting wires are individually and discretely pulsed sequentially to generate a time varying electrostatic field adjacent to the writing table that can be sensed by the sensor. The signal sensed by the sensor and the signals used to drive the time-varying electrostatic field are electronically processed and converted into electrical signals representing the position of the sensor relative to the writing table.

Abstract: A writing pen capacitively detects and amplifies signals generated by a writing table that produces a varying electrostatic field near its writing surface. The pen cartridge, which senses the signal, is capacitively coupled to a concentric electrode, from which the signal which has been detected may be obtained for amplification.

Abstract: A thermal nib is provided, which is heated by being directly inserted into an electrical circuit, and which enables writing on thermal paper.

Abstract: Apparatus for feeding individual sheets from a hopper, including a rotating prefeed member positioned near the exit end of the hopper and having projections for repeatedly beating the next sheet to be fed from the stack of sheets, to help separate the sheets and to urge the next sheet out of the hopper.