... .Support RTU extended protocol 3.8 Digital inputs, 4 relay outputs F2164 MODBUS GPRS RTU Technical SPECIFICATION F2164 GPRS RTU ... Terminal Unit(abbreviation: RTU).It has multiple functions (analog input,relay output, digital input, digital output, pulse counting and wireless data ... report.u Support 4 optocoupler isolated output ports and 4 relay outputs controlled via MODBUS RTU protocol. u RS232/RS485/ ...