The CEW4Quadset system monitors up to 4 remote sensors wirelessly over a 900MHz or 2.4GHz network. This results in substantial savings in labor and material costs during installation. While typically used for enclosed parking facilities where CO and NO2 (for Diesel fumes) are the gases detected, the CEW4 can monitor other toxic gases such as carbon dioxide, ammonia and hydrogen sulfide or combustibles such as methane and propane. System configuration is done through a removable keypad prohibiting unauthorized tampering. The CEW4 utilizes electrochemical CO and NO2 sensors each covering an area of a circle having a 50ft radius.