User's Guide
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HT81x User Guide 
GNU GPL INFORMATION 
The firmware for the HT81X contains third-party software licensed under the GNU General Public License 
(GPL). Grandstream uses software under the specific terms of the GPL. Please see the GNU General 
Public License (GPL) for the exact terms and conditions of the license.   
Grandstream GNU GPL related source code can be downloaded from Grandstream web site from: 
http://www.grandstream.com/support/faq/gnu-general-public-license/gnu-gpl-information-download 










