The Elta 149-EC-CO2TH3B is a multi-function room sensor that accurately monitors carbon dioxide (CO2), temperature, and relative humidity levels. Designed to comply with Part F guidance, it supports both +24V AC/DC and 230V 50/60Hz power supplies. The sensor provides a linear +10V output suitable for controlling speed controllers or EC fans, alongside a VFC relay for CO2 alarm signaling. Optional communication protocols include BACnet and Modbus. Additionally, it features an LED indicator that displays CO2 levels through red, yellow, and green signals, ensuring easy visual monitoring.