Abstract: This controller may be used to direct operations of a remote station impact line printer whose data source is a host computer. The controller includes a microprocessor (CPU), a memory large enough to accomodate a plurality of lines of textual data, and host computer and printer interfaces arranged in a firmware implementation. A multiline buffering feature includes capability for receipt of incomplete lines and printing of partial lines. An overstrike feature includes capability for printing more than one character at the same print point (e.g., underlining, or "0") without intervening horizontal escapement commands such as backspace or carriage return.

Abstract: An electron beam deflection circuit useful in cathode ray tube displays which employ television scanning principles. The deflection circuit is characterized by transformer coupling between a source of horizontal drive signal and a switching transistor for the horizontal deflection coil. Energy stored in the transformer during the scan and retrace time is utilized during the scanning time to provide base current to the switching transistor. In addition, the transformer has a second primary winding connected in the emitter circuit of the switching transistor in a manner to allow positive feedback. The positive feedback enhances and sustains the base current during scanning time and controls its magnitude. The circuit is advantageous in that it eliminates the need for precise waveshaping circuits at the input to the switching transistor and lowers the power requirements for the circuits which precede the switching transistor.

Abstract: A computer system having two busses which are shared by one or more processors, one or more memories, one or more input/output channels and a bus control mechanism. One of the busses is used for the transmission of original messages from the processors and/or I/O channels to the memories or the bus control mechanism. The other bus is used for the transmission of reply messages by the memories or the bus control mechanism to the senders of original messages requiring a reply. The bus control mechanism includes a first control means for controlling priority and usage of the first bus and a second control means, independent of the first control means, for controlling reply message traffic over the second bus. The reply message control means is arranged to handle reply message traffic on a priority basis and a time availability basis so as to prevent hang up of the reply message bus.

Abstract: A print hammer mechanism with a flexible interposer selectively moveable from a normal position into the path of a rotating impeller tooth which engages the interposer driving it and the associated hammer toward a print line to impact a print medium with a type die on a moving carrier. The interposer is flexible in the plane of motion of the hammer and the impeller tooth which allows slower and more controlled acceleration of the hammer and enhances the wear of the materials used to fabricate the hammer, interposer and impeller tooth. Uncontrolled oscillation of the flexible interposer and, hence, multiple strikes and multiple rebounds from the print hammer back stop are prevented by means of a mechanical linkage which captivates the interposer to the hammer for travel with the hammer but also allows the interposer to move from its normal position into the path of the impeller tooth and to return to its normal position.

Abstract: An apparatus and arrangement is disclosed for controlling the sharing of an electronic memory between a number of memory users, at least one of which requires transfers of blocks of data on a high priority basis. Access to the memory is controlled by means of a modified time division multiplexing scheme whereby a set of time slots is assigned for performing memory accesses requested by high priority memory users, but, during times in which no high priority users are using the memory, these time slots may be used by other memory users in the order of pre-assigned priorities. Independent output data paths are provided for the respective high and low priority data transfers.

Abstract: Electronic display system in which a single memory is timeshared by a plurality of display units each including a cathode ray tube (CRT) television monitor capable of displaying a frame of characters in the form of one or more lines as well as a central processing unit and a number of input/output units. Character codes representing the characters in each character line being displayed are stored in blocks of storage locations in the memory, one character line per memory block. A plurality of frame display programs, one for each display element, are stored in separate blocks of storage locations. Each program specifies the order in which the character lines are to be displayed by its corresponding display element. A refresh control unit common to all of the display units includes a basic line counting means which is employed to sequentially execute the frame display programs in retrieving the character codes from the memory and loading them into unit line buffers for the various display units.

Abstract: A print hammer mechanism with a flexible interposer selectively moveable from a normal position into the path of a rotating impeller tooth which engages the interposer driving it and the associated hammer toward a print line to impact a print medium with a type die on a moving carrier. The interposer is flexible in the plane of motion of the hammer and the impeller tooth which allows slower and more controlled acceleration of the hammer and enhances the wear of the materials used to fabricate the hammer, interposer and impeller tooth. Uncontrolled oscillation of the flexible interposer and, hence, multiple strikes and multiple rebounds from the print hammer backstop are prevented by means of a mechanical linkage which captivates the interposer to the hammer for travel with the hammer but also allows the interposer to move from its normal position into the path of the impeller tooth and to return to its normal position.