User Guide for SIP-T42G IP Phone3GNU GPL InformationYealink SIP-T42G IP phone firmware contains third-party software under the GNU General Public License (GPL).Yealink uses software under the specific terms of the GPL. Please refer to the GPL for the exact terms andconditions of the license.The original GPL license, source code of components licensed under GPL and used in Yealink products can bedownloaded online:http://www.yealink.com/GPLOpenSource.aspx?BaseInfoCateId=293&NewsCateId=293&CateId=293.About This GuideThank you for choosing the SIP-T42G IP phone, an ultra-elegant Gigabit IP phone which is exquisitely designedto provide business telephony features, such as Call Hold, Call Transfer, Busy Lamp Field, Multicast Paging andConference over an IP network.This guide provides everything you need to quickly use your new phone. First, verify with your systemadministrator that the IP network is ready for phone configuration. Also be sure to read the Packaging Contentsand Regulatory Notices sections in this guide before you set up and use the SIP-T42G IP phone.