BPHG100 transmitter measures CO2 concentration in in-door atmospheres and converts it into standard current or voltage signal. BPHG100 uses dual nondispersive infrared (NDIR) carbon-dioxide sensor providing improved accuracy and sensitivity as well as low temperature and humidity dependence. The transmitter can be equipped with local 4-digit LED display and RS232 serial interface. BPHG100 mounting variants include free or duct installation with top or bottom mounted connector. BPHG100 application area includes indoor air control, ventilation, air-conditioning, mushroom control, etc.