SDT-4 pipeline type temperature/humidity transmitter used for measuring the temp. and humidity of air conduit. inner sensor integrate sensing element and signal processing,output fully standardized digital signal .making use of patent technology of CMOSens®, ensure that the product with extreme reliability and stability for long term. The sensor include one hygrometric sense organ of capacitive polymer,one thermometric organ made by use energy gap material. Meanwhile ,in the same IC, no-seam connection with 14 digits A/D converter and serial interface circuit .so, this product with the advantage of excellent quality ,super-quick response ,strong anti-interference .offering the active output signal ,widely used in HVAC/R and so on temp. and humidity auto controlling system.