Videotelephone apparatus for transmitting high and low resolution video signals over telephone exchange lines
Patent 4888795 Issued on December 19, 1989. Estimated Expiration Date: 
June 28, 2008. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
June 28, 2008. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 3781477 Video telephone Patent #: 4258387 InventorsAssigneeApplicationNo. 212498 filed on 06/28/1988US Classes:348/14.14, Still frame (e.g., freeze frame)348/14.12, Transmission control (e.g., resolution or quality)379/100.17, Transmission scheme379/916TOUCH SCREEN ASSOCIATED WITH TELEPHONE SETExaminersPrimary: Ng, Jin F.Assistant: Lewis, Bonita Attorney, Agent or FirmInternational ClassesH04M 011/00H04N 007/14 Foreign Application Priority Data1987-06-30 JPAbstractIn an audiovisual communication, a first high fram rate video signal is derived from a motion image and converted to a low fram rate low resolution multiframe signal. A second high frame rate video signal is derived from an still image and converted to a single frame high resolution signal. Because of the low frame rates, the frequencies of the low and high resolution signals are within the range of frequencies of a telephone exchange line. A switching matrix is provided to sequentially couple both the low and high resolution signals to a transmission line in response to a mode select signal. The single frame high resolution signal is stored into a memory at the receiving end and repeatedly retrieved out of the memory into a display through the switching matrix.Other References
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