IFX Mail Archive: IFX> LZW compression IP

IFX Mail Archive: IFX> LZW compression IP

IFX> LZW compression IP

From: John Pulera (jpulera@minolta-mil.com)
Date: Fri Sep 06 2002 - 20:47:03 EDT

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    Regarding the possible use of LZW compression in the proposed PDFax data
    format for IPP Fax:

    The LZW algorithm is patented by both IBM (4,814,746) and Unisys (US patent
    4,558,302, European patent 0,129,439 - Japanese and other patents pending),
    while British Telecom (BT) holds a similar patent. The IBM patent
    application was filed three weeks before that of Unisys, but the US patent
    office apparently failed to recognize that they covered the same algorithm.
    (The IBM patent is more general, but its claim 7 is said to be exactly LZW.)
    The LZW patent, as well as its international counterparts, and similar
    patents filed by others, are expected to remain valid for at least 20 years
    from the original filing date, i.e. until June 19, 2003

    On January 27, 1995, Unisys announced new licensing policies regarding "The
    Welch Patent". These include a .45% royalty on the total unit selling price
    of GIF/LZW products (minimum $0.10, maximum $10.00 per unit) and a .65%
    royalty on GIF/TIFF/LZW products (minimum $0.20, maximum $25.00). For
    further information and a copy of the written agreement it is possible to
    call Unisys at +1 215 986-4411, or email lzw_info@unisys.com


    John Pulera
    Minolta Systems Laboratory
    11150 Hope St.
    Cypress, CA 90630
    (714) 898-4593 x115

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