1. Quad-band, 3G WCDMA, 3G CDMA, can work in the worldwide GSM and 3G Networks; 2. No call charges. the GPRS-3G Gate Opener rejects the call from authorized number then carries out the turn ON/OFF action on the first 'ring'; 3. Multiple applications. (gates, bollards, barriers, garage doors, shutters and access doors or machines); 4. Add or remove users by SMS Text command or over GPRS Network or USB Port; 5. No need to provide a remote control or keys for different users; 6. Up to 999 authorized phone numbers can be configured at the specified time; 7. Remotely upload the historical data or via USB port, the record capacity is 10000events; 8. 1 Digital inputs for motion sensors or other sensors to protect your door and windows; 9. 1 input special for monitoring door status and automatically armed when door closed; 10. 1 output with relay rating 3A/240VAC for connecting the switch of the door or machines; My skype:GsmrTuSystem