Model:S273 Name:GSM 3G M2M RTU (8DI+6AI+4DO+1TH+1USB+1RS232/485+64Registers) The GSM 3G M2M RTU is a multi I/O port remote terminal unit, through the RS232/485 port can connect intelligent meters or PLC. It is special for BTS monitoring, remote data acquisition, telemetrically, BTS access control and other applications. It supports voice communication, SMS, GPRS, 3G communications. Mainly Features: 1. ARM® Cortex™-M4 32 Bit RISC Core, 168 MHz inside, RTOS system; 2. Widely Rated voltage range, 9~36VDC, Inbuilt large capacity rechargeable backup battery; 3. 4G SD card for save historical data, USB port for configuration and upgrade firmware; 4. 6 analog inputs, 12bits, supports 0-5V, 0-20mA, 4-20mA; 5. 4 Relay outputs, 5A/30VDC,5A/250VAC; 6. 8 digital inputs, dry contact or level input. One of the input can be used as counter; 7. 1 temperature probe input, 1 humidity transducer input; 8. I/O ports with opto-isolated, RS232/485 with 15KV ESD protection; 9. 2 IP data centers, supports Modbus TCP,TCP/IP protocol over GPRS/3G network; 10. RS232/RS485 can performs Modbus RTU Master, Modbus RTU Slave, supports 01,02,03,04,05 code, up to 64 registers, the register arise alarm also can send SMS to alert; 11. RS232/485 can be used as data transparent transmission for different intelligent meters or PLC; 12. Automatically resend the data while communication failure, GPRS failure will alert by SMS text; 13. Supports remotely restart the RTU, and configure it by SMS commands remotely; 14. Supports over voltage protection and phase-reversal protection; 15. 10 SMS Alert and auto dial numbers, can program to receive specified alarm message. 16. 10 access control authorized numbers, can open the BTS door or turn on/off machine with a free charge call at the specified time.