The T1551 outside air enclosure operates with a supply voltage of 18-30 VAC at 0.7 VA 50/60 Hz or 18-42 VDC at 29 mA, featuring a selectable signal output of 0-5 V / 0-10 V or 4-20 mA / 500 Ohm for CO2, humidity, and temperature measurements, compatible with T8000 series CO2 sensors.