The ZigBee Specification is available to individuals, companies and institutions free of charge for all non-commercial purposes (including university research, technical evalua- tion, and development of non-commercial software, tools, or documentation). For ease of use, clearly marked errata have been incorporated into this document. These errata may not have been subjected to an Intellectual Property review, and as such, may contain undeclared Necessary Claims. No part of this specification may be used in development of a product for sale without becoming a member of ZigBee Alliance.