Abstract: A system and method to avoid transmit underruns from a host system to a communication network using an adjustable threshold on a frame basis. The host system includes a device driver, host descriptors and host buffer. The host descriptor define the number of blocks of data to be transferred from the host to the network via a Media Access Control (MAC) device. The MAC device includes a processor, a transmit storage device, and a medium independent interface coupled to the network. The MAC device is connected to the host system via a data bus. A host descriptor is generated for each frame of data transferred by the MAC device from the host to the network. The descriptor is generated by the device driver and provides the MAC processor with a block size of data to be transferred and a threshold in each frame indicating the number of blocks of data to be transferred from the host system to the MAC device to avoid an underrun before transmission to the communication network.

Abstract: A computer memory subsystem is comprised of one or more Dynamic Random Access Memory (DRAM) arrays with on-chip sense latches for storing data outputted from the DRAM, an on-chip Static Random Access Memory (SRAM) functioning as a Distributed Cache and an on-chip multiplexor. A first data bus interconnects the sense latches, the SRAM and the multiplexor. A second data bus interconnects the multiplexor and the SRAM. A memory controller generates signals which cause information to be extracted from the DRAM while the contents of the SRAM is unchanged or vice versa.

Abstract: There is provided a method of regulating access to a unidirectional bus transmission system to which a plurality of stations identified by labels are connected, on which system data are transmitted in time slots which are released in numbered cycles by a headend unit, and in which said headend unit sends, for each of said cycles, a request poll message carrying the respective cycle number. The method comprises i) logically combining a source station label and a destination station label, ii) deriving a first control number from the logical combination of the source station label and the destination station label, iii) using, for requesting slots in which to transmit said data, a request poll message carrying a cycle number which corresponds to said first control number, and iv) subsequently transmitting said data in slots of a cycle whose number corresponds to said first control number.

Abstract: The present invention utilizes bypass circuitry to shorten the cycle time of a cache memory by shortening the time required to perform a write through read operation (WTR). The bypass circuitry senses when a WTR operation will occur by comparing the encoded read and write addresses to determine when the encoded addresses are equal. When the encoded addresses are equal, a WTR operation is requested and the bypass circuitry sends the data to be written into memory to both the write address location and the cache output buffer. The bypass circuitry does not wait to access the data from the memory cells through the read decode, rather, it directly sends the data to the output buffer. The bypass circuitry provides a parallel read and write operations instead of serial operations during a WTR, thereby shortening the machine cycle time.

Abstract: A servo-controlled recirculating automatic document feeder (RADF) includes a plurality of independently driven document transport devices. A picker mechanism separates documents in seriatim from a stack. An entry turnaround transport device buffers and delivers picked documents to a platen transport device for exposure. After exposure, the document is transported along a simplex or duplex path for duplex or simplex copying. The document is then buffered in an exit turnaround transport device and is subsequently returned to the stack. Each transport device is independently driven by a motor and a closed-loop servo. A common reference oscillator generates source signals for the servo-loops. A microcomputer operates on the source signals and generates reference signals for driving the transport devices.

Abstract: A device for feeding sheets from a supply station aligning the sheets in an X, Y and .theta. coordinates and then gating the sheet into a work station such as the transfer station of a copier. The device includes a pair of independently servo-controlled motors disposed on opposite sides of the sheet. Each motor drives a nip roller which transports the copy sheet. Sensors are disposed to generate signals representative of sheet position in the X, Y and .theta. coordinates. A controller uses the signals to adjust the angular velocity of the motor so that the sheet is squared and is gated onto the work station. The sensors and controller are utilized to measure different parameters associated with the sheet.

Abstract: A compact single bin finisher adaptable to form collated sets of copy sheets outputted from a copier/duplicator. The finisher includes an output tray adapted to support the collated sets and to support copy sheets during accumulation of a set. A set accumulation module having an accumulation platform is disposed in a plane which is displaced both horizontally and vertically from the output tray. A transport device carries sheets into the accumulation module. A predetermined number of sheets form a set which may be stapled and is ejected onto the output tray.

Abstract: A stapler mechanism for fastening variable thickness documents includes a stack receiving receptacle disposed between the head/hammer assembly and the clinching or anvil assembly of said stapler. A sensing device is coupled to the stapler mechanism and generates control pulses indicative of relative motion between the head/hammer assembly. A controller processes the signals and generates control signals which vary the stroke and the force driving the hammer and returns the head/hammer assembly to its home position following a stapling cycle.

Abstract: In the use of a scanned light beam for optical imaging, a random motion modulation is applied to the light beam orthogonally to the scan direction to break up any unscanned or overlapped interstices between adjacent scan lines to make the interstices appear nearly invisible.

Abstract: An automatic vacuum document feeder particularly adapted for feeding sheet-like documents in seriatim from a stack onto a utilization device, such as the document platen of a convenience copier. The documents are disposed in a tray. A vacuum lifter descends and lifts the topmost document along a vertical path to a position above the stack and beyond the bottom surface of a vacuum transport. The vacuum transport is disposed in a plane perpendicular to the vertical path of the vacuum lifter. The vacuum transport strips the document from the vacuum lifter and transports the document to the utilization device. The entire system is configured so that there is no relative motion occurring between the document being transported and the transport hardware. A document restraint device, including air jets and stripper fingers, coact with the stack to eliminate double feed.

Abstract: An improved offset collator comprising a sheet gripper/injector transport station and an oscillating sheet receiving station. Copy sheets are transported to the sheet gripper/injector transport station in a specified sequence whereupon they are gripped by the transport station, and in a reciprocating motion, transported to the oscillating sheet receiving station where they are injected into a stack of sheets and released. The oscillating sheet receiving station is synchronized with transport station such that the copy sheets are inserted in the oscillating sheet receiving station in an alternate offset posture. A cooperating logic control system causes the sheets to be inserted into the oscillating sheet receiving station in the proper order and offset. After offset collation is completed, the offset stapling station then cooperates with the oscillating sheet receiving station to staple sets of sheets still in their offset posture.

Abstract: An apparatus and method is provided for segmenting characters generated by an optical scanner. The apparatus also identifies underscores. The underscores are then masked and subsequent processing devices are informed of the existence of said underscores. Input video raster scans representative of a portion of a line of textual material are loaded into a video buffer. The video raster scans are broken up into a plurality of sections. The horizontal histogram (number of black pixel counts) associated with each section is determined. The baseline, vertical histogram and word location for each line of data to be segmented is determined. A find character unit finds the boundaries for each character. The character is sequentially transferred from the video buffer to a character output buffer.

Abstract: The contamination by ink of an ink jet printing system at start-up and shut-down is eliminated by moving the normal operational gutter from its print position along the flight path of the ink droplets to a position immediately adjacent to the nozzle plate of said head. The charge electrodes and the deflection electrode are moved out of the path of the gutter as it advances towards the nozzle plate.

Abstract: An emergency communication system used by stranded motorists to summon help when travelling on toll roads or other limited access highways. The emergency communication system comprises a portable, self-powered, hand-held transceiver set which transmits coded distress signals and directional signals, when activated, and cycles until reception of an answer back signal. The signals or messages from the portable transceiver are transmitted at incrementally increasing power levels to a single or a plurality of roadside relay stations spaced strategically along a limited access highway or toll road. The relay stations retransmit the signals to a terminal station which has means to decode the signals and determine the location of the repeater station nearest to the stranded motorist.