LZW Patent and Software Information
License Information on GIF and Other LZW-based Technologies
More and more people are becoming aware that the reading and/or writing of GIF images requires a license to use Unisys patented Lempel Ziv Welch (LZW) data compression and decompression technology, including United States Patent No. 4,558,302, Japanese Patent Numbers 2,123,602 and 2,610,084, and patents in Canada, France, Germany, Italy and the United Kingdom. Since January of 1995, Unisys has entered into almost two thousand license agreements for use of GIF and other LZW-based technology.
As a result of both this extensive licensing and changes in the use and marketing of GIF and other LZW-based products, Unisys has had to adjust its licensing policies to reflect these changes and the needs of existing and future licensees.
Microsoft Corporation obtained a license under the above Unisys LZW patents in September, 1996. Microsoft's license does NOT extend to software developers or third parties who use Microsoft toolkit, language, development or operating system products to provide GIF read/write and/or any other LZW capabilities in their own products (e.g., by way of DLLs and APIs). The complete statement by Microsoft can be found at Microsoft's developer-oriented Web site. Software developers and third parties who wish to include Microsoft toolkit, language, development or operating system products in their own products for providing GIF or any other LZW capability should contact Unisys for a license as instructed below. Other forms of LZW are, for example, TIFF-LZW, PDF and Postscript-2.
Unisys has frequently been asked whether a Unisys license is required in order to use LZW software obtained by downloading from the Internet or from other sources. The answer is simple. In all cases, a written license agreement or statement signed by an authorized Unisys representative is required from Unisys for all use, sale or distribution of any software (including so-called "freeware") and/or hardware providing LZW conversion capability (for example, downloaded software used for creating/displaying GIF images). In certain cases, no license fees may be required, but this needs to be evidenced by a written agreement or written statement signed by an authorized Unisys representative.
Unisys therefore cautions recipients, users and distributors of hardware or software products containing LZW conversion capability to make sure that they are lawfully acquiring and/or distributing licensed LZW software. The fact that a product includes a notice regarding the need for a Unisys license (or a statement that the software is "freeware") should NOT be relied on to avoid liability, since the distributor may not in fact be authorized to distribute the LZW software and may itself also be subject to liability along with the recipient. You should also be aware that Unisys licenses have a limited field of use and may not allow your intended use even if the vendor/distributor has a Unisys license. For example, the typical Unisys license for standalone software does NOT permit copying, modification, resale, use on a server or in a network, or use for Internet/Intranet/Extranet or Web site operation. Other limitations may also be applicable. Upon request, Unisys will, in most instances, be able to advise you whether a specific software vendor is licensed by Unisys and the scope of this license.
Currently applicable information as to Unisys licensing policies for products using LZW (GIF, TIFF-LZW, PostScript, Portable Document Format (PDF), V.42bis, etc.) can be obtained by contacting the following:
Welch Patent Licensing Department; Unisys Corporation; Mail Stop E8-114; Unisys Way, Blue Bell, PA 19424. Via the Internet, send E-mail to LZW_INFO@UNISYS.COM. Via facsimile, send inquiries to Welch Patent Licensing Department at 215-986-3090.
A special license (read in English or Japanese) is available for operators of Intranet and Billboard Web sites.
The above is presented for information purposes only, and is subject to change by Unisys. Additionally, this information should not be considered as legally obligating Unisys in any way with regard to license availability, or as to the terms and conditions offered for a license, or with regard to the interpretation of any license agreements. You should consult with your own legal counsel regarding your particular situation.