In-Situ RDO PRO Process Optical Dissolved Oxygen Sensor Manual - Manual (Page 13)

5.3 SDI-12 (3 wire)
Signal Color
Ground/Return Black
External Power (9.6-16 VDC) Red
RS485 (-) Green
RS485 (+) Blue
SDI-12 White
 Cable length must not exceed 60.96 m (200 ft.)
Page 13 Controller Requirements and Connections