Abstract: A display system which has a source of blocks of codes representing characters to be displayed and a display device which converts the blocks of codes to lines of visually displayed characters is provided with a buffer memory which connects the source to the display device. The buffer memory includes a random access memory (RAM) with addressed registers for storing the codes and an address generator in the form of a counter. When a block of codes is transferred from the source to the buffer memory, the counter is initialized and as each code is transmitted to the buffer memory the counter is incremented. Each time the block of codes is transferred from the buffer memory to the display device the counter is again initialized and with the reading of each code from the memory the counter is again incremented. The buffer memory includes two identical RAMs and is controlled such that while one RAM is being loaded the other RAM is being read.

Abstract: A printer has a horizontally movable carrier which supports a print head including a print element on which are disposed type characters in a two dimensional array with the element controllably movable by motors in two degrees of freedom to selectively position each type character opposite a record-medium-carrying platen for printing. The print head is on a rocker having a cam follower which cooperates with a cam on a shaft driven by a variable speed motor which is also on the carrier. During printing the motor speed is controlled so that the print element is driven against the platen with a force related to the particular character being printed. The motor speed is further controlled so that there is not only a minimum wait between the printing of successive characters but there are also minimum accelerations and decelerations of the motor.

Abstract: In a keyboard having two depressable key switches which receive pulses of a first given width and transmit in response thereto pulses whose width is a function of the mechanical travel of the key switch, the travel of the key switches is detected by feeding a pulse of a first given width alternately to the key switches, sensing for the width of pulses transmitted by the key switches in response to receipt of the pulses of first given width. When the width of a pulse transmitted by one of the key switches in response to the receipt of one of the pulses of the first given width exceeds a second given width which is less than the first given width, there is fed a series of the pulses of first given width only to such one key switch and none of the pulses to the other of the key switches.

Abstract: In a magnetic recording system utilizing a non-return-to-zero format the reproduced recording is fed to positive and negative threshold detectors having no need for electrical hysteresis as well as, via differentiator means, to a zero-crossing detector. The signal from the positive threshold detector and one polarity of the signal from the zero-crossing detector are used to trigger a latch means to a first state to emit a signal having a first level, and the signal from the negative threshold detector and the other polarity of the signal from the zero-crossing detector are used to trigger the latch means to a second state whereby the signal emitted by the latch means is switched to a second level.

Abstract: A printer has a print shell on which are disposed type characters in a two dimensional array with the shell controllably movable in two degrees of freedom to selectively position each type character opposite a record-medium-carrying platen for printing. In addition, during printing the shell is driven against the platen with a force related to the particular character being printed, and associated with the printing is an indexing or transverse spacing of the print shell to expose new portions of the record medium for printing.

Abstract: A finger operated switching device includes a key assemblage having a key and a key magnet which moves relative to a biasing magnet wherein the magnets are so dimensioned and mutually positioned so that the key assemblage is biased to a retracted position and when the key assemblage is pushed to an extended position the force required first increases to a peak and then rapidly decreases.

Abstract: In a printer wherein a ribbon is driven against a platen by a print element there is provided a ribbon lifting mechanism having a one revolution motor which drives, via a n-to-1 reduction gear, a ribbon guide to pivot to different positions whereby different transverse portions of the ribbon are interposed between the impact region of the print element and the platen.

Abstract: In a system for recording bits in elements along a moving magnetic medium wherein a first valued bit is represented by a pulse of a first width, length or duration, and a second valued bit is represented by a pulse of a second width, length or duration, there is included the improvement of changing either the first width or said second width when the bit to be recorded and the bit previously recorded have the same value.

Abstract: There is disclosed a typewriter using a single element print head wherein the tilt and rotate positions for character selection are obtained by servo systems driving tilt and rotate shafts. The system utilizes a digital multiplexing system whereby common elements in the servo channels are time shared. One common element is a binary arithmetic unit which compares binarily represented actual and desired position values of the shafts to fetch from a memory desired velocity information. The fetched velocity information in binary form is compared with the binarily represented actual velocity of the shafts to generate signals for energizing the servo motors which drive the shafts.

Abstract: A vertical deflection circuit which vertically deflects the electron beam of a cathode ray tube in response to vertical synchronizing pulses comprises a vertical deflection coil having one end connected to a reference voltage source and the other end connected to a first and second current generating means. The first current generating means generates a current having a repetitive sawtooth waveform which is in synchronism with vertical synchronizing pulses; and the second current generating means generates a constant current whose amplitude is selectively adjustable to control the vertical starting position of the electron beam of the cathode ray tube.

Abstract: A video amplifier for driving an electron beam intensity controlling electrode of a cathode ray tube comprises at least one solid state high speed binary switch which is connected via a coupling capacitor to the controlling electrode while a D.C. restoration means eliminates the chance of any droop in D.C. level of the signal fed to the controlling electrode.

Abstract: A data communication terminal with a single data communications means is selectively connected via a first data coupler to a dialed telephone facility or via a second data coupler to a teleprinter facility.

Abstract: The current flowing through the horizontal deflection coil of a cathod ray tube is controlled by a transistor which is switched between saturation and cut off by a circuit having a pulse generator for generating a pulse in response to a horizontal synchronizing pulse. The leading edge of the generated pulse is delayed before being applied to the controlling transistor which switches sometime thereafter due to the storage time of the transistor. To insure that the blanking of the electron beam of the tube takes place during the retrace time, the blanking interval is set to occur a period of time after the horizontal synchronizing signal which is less than the sum of the storage time of the transistor and the time which the leading edge of the generated pulse is delayed.