The TAPR Open Hardware License is a license used in open source hardware projects. It was created by Tucson Amateur Radio Package (TAPR), an international amateur radio organization. Version 1.0 was published on May 25, 2007.
According to the official website, the GNU General Public License , the OHL is designed to guarantee freedom to share and to create. It forbids anyone who receives rights under the OHL to deny any other licensee those same rights to copy, modify, and distribute documentation, and to make, use and distribute products based on that documentation.  
Although the TAPR OHL aims to maintain the philosophy of open-source software , there are some differences in physical reality which require some differences in licenses. As a result, the license defines two conditions, Documentation, as in design and products, as in the physical products created from them.
According to the text of the license, 
- You may modify the documentation and make products based on it.
- You may use products for any legal purpose without limitation.
- You may distribute unmodified documentation, but you must include the complete package as you received it.
- You may also be interested in the following article (s) in this article.
- You may distribute the documentation or products based on it, if you:
- License your changes under the OHL.
- Include those modifications, following the requirements stated below.
- Attempt to send the modified documentation by email to any of the developers who have provided their email address. This is a good faith obligation-if the email fails, you need to do more and may go on with your distribution.
- If you create a design that you want to license under the OHL, you should:
- Include the OHL document in a file named LICENSE.TXT (or LICENSE.PDF) that is included in the documentation package.
- TAPR Open Hardware License (www.tapr.org/OHL) “in each documentation file. While not required, you should also include this artwork and the product itself; If space is limited the notice can be shortened or abbreviated.
- Includes a copyright notice in each file and printed board artwork.
- If you want to be notified of any changes that may be made, please include your email address in a file named “CONTRIB.TXT” or something similar.
- Any time the OHL requires you to make documentation available to others, you must include all the materials you get from the upstream licensors. In addition, if you have modified the documentation:
- You must identify the changes in a text file (preferably named “CHANGES.TXT”) that you include with the documentation. TAPR Open Hardware License. “These changes are licensed under the TAPR Open Hardware License.”
- You must include any new files you created, including any manufacturing files.
- You must include both “before” and “after” versions of all files you modified.
- You may also have a look at the following pages.
The TAPR OHL is the license for the materials from the Open Graphics Project as of April 7, 2009.  The TAPR OHL is the license for the materials from Lotus Green Data Center as of July 28, 2008.  [6 ]
There is also a TAPR Noncommercial Hardware License, which is similar but does not allow for commercial application.  As of September, 2012, TAPR has officially deprecated the NCL.
Former OSI President Eric S. Raymond expressed some concerns about certain aspects of the OHL. According to Raymond, the license has “lots of problems” and that it “strips the word ‘distribution’ of its normal meaning, assuring lots of contention over edge cases.”  There are also concerns that the Open Hardware License may merely place the design and / or idea into the public domain by enabling it to secure the benefits of patent protection.  Like all Open Hardware Licenses, the OSI has not chosen to review the TAPR license. 
- Open Hardware License
- Open source hardware
- Jump up^ TAPR OHL
- Jump up^ Ackermann_Open_Source_Hardware_Article_2009on tapr.org
- Jump up^ TAPR Open Hardware License
- Jump up^ The Open Graphics Project is making the OGD1 schematics and artwork available under the TAPR Open Hardware License
- Jump up^ Lotus Green Data Centers forgoes economic protection of patenting
- Jump up^ TAPR Open Hardware License published at LotusGreenDataCenters.com
- Jump up^ TAPR NCL
- ^ Jump up to:a b Ars Technica: TAPR introduces open-source hardware license, OSI skeptical .
- Jump up^ Novelty And Non-obviousness, Conditions For Obtaining A Patent: US Patent and Trademark Office.