... external supply; can link to PC through communcation interface.2. Ordering Code:Model and TypeInputAnalog ouputAlarmCommunicationAuxiliary supplyDS8- ... Alarm 1,2,3 relay output With RS485 interface DC 12V 3. Technical Specifications:Property projectSpecific ... 24V/30mA or DC 12V/30mACommunicationRS485 or RS232 interface (Modbus protocol)Ambient temperature0~50CStock temperature-10~60CHumidity35 ...