This is a cost-effective trunk gateway equipment  specific design for open source market to work with Asterisk/Elastix/small IPPBX. Its built-in echo canceller function and voice decoding conversion function. Users can flexibly select G.711A/U, G.729, G.723, iLBC a variety voice decoding  and easily complete  IP and PSTN voice and signal converting.  In addition, it provides  friendly  GUI configuration interface, users can freely configure  and manage the equipment.