Recommendation ITU-T K.123 describes the requirements for radiated and conducted emissions from electrical systems installed in telecommunication facilities. Electrical systems in the scope of this Recommendation include inverter driven electrical equipment including the air conditioners needed for the operation of telecommunication systems, personal computers, displays, printers, maintenance robots, and security systems including surveillance cameras. Their electrical systems include power conversion devices and electronic circuits which may generate conducted and radiated electromagnetic disturbances and cause degradation of the performance of nearby telecommunication systems.