The Series RSM Room Status Monitor is designed for critical low differential pressure applications that require stringent pressure monitoring and alarming. The Series RSM can be configured to monitor positive or negative pressure in protected environments and hospital isolation rooms per CDC guidelines. The RSM is a complete system that includes a backlit RGB LCD display with a graphic user interface which enables access to pressure, security, calibration, and alarm setup. The touch-screen displays menus that guide the user through setup, as well as setting up password protection. Red and green LED's and a local audible alarm (with time delay feature) alert personnel to system status. The RSM has a NEMA 1 (IP20) rated fire retardant plastic for indoor applications. True differential pressure is displayed with a resolution of 0.001 in w.c. The very low pressure capacitance is dead ended and avoids the potential for cross contamination of the room and reference space as well as eliminating drift that results from fouling of flow based sensors, which by nature have a flow path connecting the protected and reference spaces. Additionally, there are two levels of password protection available as well as optional BACnet MSTP communication. A calibration certificate is provided with every unit.