Abstract: A data communication station comprises a first and second data terminals operating under first and second transmission standards, and a selective switching means to connect those terminals to a single communication line; the first data terminal is usually a teleprinter or other character-by-character terminal capable of operating under applicable standards such as those for Economy Telex or for DDD (Direct Distance Dialing) ASCII transmissions, whereas the second data terminal may be a facsimile machine or other graphics terminal operating under the CCITT T-series standards. In one embodiment the switching means is a free-standing control unit that may be connected to virtually any conventional data terminals; in another version the switching means is incorporated in an input/output board in one data terminal and utilizes a part of the logic of that data terminal.

Abstract: A communication adapter for a personal computer or computer terminal is interposed between the computer process unit and its accessory units, such as a keyboard, a printer and a display monitor; the adapter includes a data memory for storing data and actuation signals from the keyboard, from the process unit, and from a communication port on the adapter, together with transmission logic circuits for transmitting data from the memory through the communication port, and accessory logic circuits for supplying data from the memory to the printer and to the monitor.

Abstract: In a method and apparatus for magnetic printing on plain paper, using a dot matrix format, a sheet of paper is positioned on the surface of a thin, elongated strip platen of permanent magnet material and a magnetic printhead scans the platen, magnetizing dot size portions of the platen in dot matrix patterns defining magnetic images of the data characters in a line of text; limited quantities of toner are applied to the paper to develop those images as visible characters on the paper. After development, the platen is displaced transversely of the paper surface to an inactive position, permitting movement of the paper, without disturbance of the developed images, to bring the line of developed character images to a separate fixing station at which fixing is effected without incurring the possibility of damage to the platen.

Abstract: A method and apparatus for character-by-character magnetic printing on plain paper, using a dot matrix format; a sheet of paper is positioned on the surface of a thin, elongated strip platen of permanent magnet material and a magnetic printhead comprising a columnar array of electromagnets scans the platen. Selective energization of the electromagnets, during each scan, magnetizes dot-size portions of the platen in dot matrix patterns defining magnetic images of the characters in a line of text; limited quantities of toner are applied to the paper generally concurrently with formation of the magnetic images to develop those images as visible characters, which are subsequently fixed on the paper surface.

Abstract: An alignment mechanism for a paper tape reader in which the motor and drive sprocket assembly is firmly, but not rigidly, affixed to a base plate of the main reader unit by a plurality of compressive spring fasteners. Arcuate slots in a motor mounting base plate, in conjunction with spring-biased retainers projecting through those slots and secured to bosses on a reader base plate, maintain the two base plates in spaced parallel relation and permit limited angular rotation of the motor and drive sprocket assembly, thus facilitating angular adjustment of the motor. A bias spring applies a torsional force to the motor assembly, forcing it against an adjustable screw stop. Adjustment of this screw results in rapid and precise single-step alignment without the often disruptive further step of tightening retention fasteners.

Abstract: A paper web take-up and storage device for a teleprinter, having a spring biased guide bail to sense paper length and a control switch that energizes a storage reel drive motor for take-up when needed, is also equipped with a paper sensor arm to detect a no-paper condition; a single switch actuator lever that is aligned with the bail, with the sensor arm, and with the control switch affords complete control for both take-up and no-paper conditions in an arrangement that allows limited reverse movement of the web back toward the printer with no appreciable resistance apart from a relatively weak bail bias spring. The reel includes a spring-latched guide flange adjustable to accommodate a number of different paper widths.

Abstract: A driver mechanism for a dot matrix printhead, including an electromagnet, an armature, and a print impact element connected to the armature by a cantilever spring, energization of the electromagnet and consequent movement of the armature to closed position driving the impact element to impact a record sheet supported on a platen; a concentrated mass load is mounted on the spring, sufficient to maintain the impact element essentially in its rest position during a substantial portion of the armature movement so that the force/travel characteristic of the spring governs movement of the impact element, with maximum force at the outset and near zero or zero force at impact. Energization of the electromagnet is interrupted when the armature closes, and a shunt circuit holds the armature closed until just before impact.

Abstract: A dielectric substrate for a thin film dot matrix thermal print head has its working surface etched or otherwise treated to selectively remove the dielectric material, in all areas which will constitute electrical connectors for the resistance heater print elements, to a depth at least equal to the sum of the thicknesses of all of the conductive films to be applied to the substrate surface in those areas, following which the working surface of the substrate is selectively coated with films of high-resistance electrically conductive material and low-resistance conductive material, with suitable adhesion films as required, to complete the print head. An outer protective wear-resistant film is also employed. The resultant print head has its resistance heater print elements and blank surface elements raised at least to the same level as the outer surfaces of the electrical connectors, and preferably slightly higher, to provide improved performance and operating life.

Abstract: An isolated line switching circuit for direct connection of a telephone, teleprinter, or like telecommunication instrument to a transmission line, comprising a solid-state optical cell including a light-actuated optical receiver that generates an electrical current when illuminated by an associated light-emitting device (LED), and a switching transistor having its emitter-collector discharge path connected in series with the transmission line; the optical receiver is connected to the base and emitter of the transistor to drive the transistor conductive when the LED is energized by an actuation signal initiated in response to a ring signal. A high-resistance emitter-to-base circuit for the transistor drains the collector leakage current (I.sub.CBO) and maintains a high off resistance even at high temperatures.

Abstract: A tape punch machine in which a change in feed hole orientation is easily accomplished.

Abstract: A descender printing system for a dot matrix printer, comprising a detector for detecting code words representative of descender characters (lower case letters, punctuation, fractions, etc.) prior to printing, and shift means for actuating the line feed mechanism of the printer to advance the paper by two or more dot heights and thereby print the descender elements of such characters below the normal base line. The shift means again actuates the line feed mechanism to return the paper to its original position when the next non-descender character is to be printed.

Abstract: A tape punch machine in which, to assure accurate and reliable tape movement, a stepping motor for feeding the tape receives two pulses for each spacing increment of the tape. The punches are selected by interposers which are not released if the same punch function is to be repeated in successive cycles of the machine.

Abstract: A method and apparatus for controlling the print rate of a column-sequential dot matrix printer actuated by an input signal comprising a sequence of code words occurring at a given maximum input rate, a print head and a print head drive operating at a speed determined by the frequency of a print rate timing signal, and a multi-stage FIFO input storage register. A multiplicity of constant-frequency print rate timing signals are generated, ranging in frequency from substantially below to substantially above a normal print rate frequency Fn approximately matched to the input rate, and a variable print rate timing signal progressively increasing in frequency from well below Fn to well above Fn is also generated; these signals are applied to the printer in accordance with a predetermined schedule, determined by the number of code words in storage at the beginning of each spacing character cycle, and in accordance with a program affording relatively smooth acceleration and deceleration of the print head.

Abstract: An all-electronic print rate control system for a high-speed column sequential dot matrix printer, using a permutation code input signal, an input storage register with a capacity of at least three code words, for storing the input data and a print timing oscillator. The control system comprises a print clock, including a plurality of countdown circuits connected to the oscillator, for generating a normal print rate timing signal and a fast print rate timing signal; the print clock can also generate a variable print rate timing signal in which the initial column intervals are longer than in the normal print rate timing signal and the concluding column intervals are preferably shorter than in the normal signal. A print clock control selects one of these print rate timing signals to control the printing speed in each print cycle, depending on printer conditions in the prior cycle; the variable signal is used whenever the printer has actually come to rest for any appreciable interval.

Abstract: A tape punch machine in which several subassemblies are arranged for accurate adjustment and easy detachment; to assure accurate and reliable tape movement a stepping motor for feeding the tape receives two pulses for each spacing increment of the tape. The punches are selected by interposers which are not released if the same punch function is to be repeated in successive cycles of the machine.

Abstract: Ribbon reversing mechanism in a high speed printer (telecircuitry) including a ribbon driving stepping motor and a print head drive motor both incrementally driven by pulses from the telegraph circuit. The gear ratios in the ribbon drive train are chosen to ensure that the ribbon is advanced in increments different than the increments of print head movement. The ends of the ribbon are provided with eyelets which are sensed by a mechanism which operates to reverse the ribbon driving motor.

Abstract: An all-electronic control system for a high-speed column sequential dot matrix printer, using a permutation code signal of given pulse rate p comprising a series of individual code words each including a fixed number of data pulses preceded by a start pulse; the control system comprises a plural-stage FIFO storage register with a capacity of at least three, and preferably four or more, code words, for storing input data, as during a carriage return of the printer. A print timing oscillator having a frequency f is coupled to countdown means that develops a normal print rate signal f/n and a fast print rate signal f/m, where f >>p and n>m. A print rate selector selects one of the print rate signals, to control the printing speed of the printer, depending on whether a code word is stored in a given stage of the storage register.