Microsoft Technology Licensing, LLC

Timex Corporation

Thomas J Dvorachek

Neil Scott Fishman

Philip S Brzezinski

J Mark Miller

The invention encompasses a system and method for serially transferring a sequence of data bits having binary values. This includes a step of displaying sequential display frames on a frame-scanning graphics display device, wherein each sequential display frame is associated with an individual group of data bits. Each group of data bits is associated with one or more data framing bits. The framing bits are inverted from one sequential display frame to the next. Within each display frame, sequentially-scanned data transmission lines are selectively illuminated to represent the individual groups of data bits associated with the display frames and their associated data framing bits. Bits having a first binary value are represented by illuminated display frame lines. Bits having a second binary value are represented by non-illuminated display frame lines. A receiving device can determine the validity of a particular display frame by determining whether the framing bits of the display frame are inverted from the framing bits of the previous display frame. Further aspects of the invention provide error detection and correction capabilities, and also provide methods of making the most efficient utilization of the data transfer mechanism.

System and method for transferring data using a frame-scanning display

The invention includes systems and methods for calibrating bit transmission rates in a computer system which uses selected raster lines of a frame-scanning display device for serial data transmission to an external receiving device. A system in accordance with the invention includes a data processor and a frame-scanning display device having a total number of available raster lines per display frame. The computer also has an internal timer which is set to generate timing signals at a predetermined frequency. The data processor is programmed to count the number of timing signals and the number of frame scans of the frame-scanning display device which occur during a selected measurement period. The selected measurement period is preferably defined by the occurrence of a predetermined number of frame scans. The data processor is further programmed to calculate a frame scan period of the frame-scanning display device based upon the predetermined frequency of the timing signals, the predetermined number of timing signals, and the number of frame scans counted while counting the predetermined number of timing signals. The frame scan frequency is used to determine the correct spacing of the data transmission raster lines relative to each other within the total number of available raster lines. This spacing establishes a desired serial transmission bit rate to the external receiving device.

Calibrating data transmission line spacing on a frame-scanning display

Method and apparatus for synchronizing the data transfer rate for downloading data from a cathode ray tube (CRT) adapted for transmission of serial data bits as light pulses appearing as spaced lines on the CRT to a portable information device having a photosensor which receives and stores binary coded data corresponding to the light pulses at a fixed pulse reception rate. The CRT displays a calibration pattern of spaced horizontal lines, which is transmitted to the portable information device where it is repetitively compared to a stored calibration character. An acceptable error free transmission is signaled by a preselected number of matches. An audible signal indicates that the transmission rate is acceptable. The CRT pattern line spacing is adjusted until the audible signal is heard. The selectable pulse repetition rate may be automatically changed in increments by periodically changing the separation between lines on the CRT until an audible output signal is heard and providing for an operator to halt the automatic process. Alternatively, the pulse repetition rate may be manually changed in increments by an operator, until an audible output signal is heard.

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Kensington, CT, United States of America

Thomas J Dvorachek