there may be additional costs involved for some products to give them a known level of immunity, it increases their perceived quality as they are able to co-exist with apparatus in the active EM environment of modern times and with fewer problems. Many countries now have similar requirements for products to meet some level of electromagnetic compatibility (EMC) regulation. Types Electromagnetic interference can be categorized as follows: narrowband EMI or RFI, which typically emanates from intended transmissions such as radio and TV stations or mobile phones broadband EMI or RFI, which is unintentional radiation from sources such as electric power transmission lines. Conducted electromagnetic interference is caused by the physical contact of the conductors as opposed to radiated EMI, which is caused by induction (without physical contact of the conductors). Electromagnetic disturbances in the EM field of a conductor will no longer be confined to the surface of the conductor and will radiate away from it. This persists in all conductors and mutual inductance between two radiated electromagnetic fields will result in EMI. ITU definition Interference with the meaning of electromagnetic interference, also radio-frequency interference (EMI or RFI) is according to Article 1.166 of the International Telecommunication Unions (ITU) Radio Regulations (RR) defined as "The effect of unwanted energy due to one or a combination of emissions, radiations, or inductions upon reception in a radiocommunication system, manifested by any performance degradation, misinterpretation, or loss of information which could be extracted in the absence of such unwanted energy". This is also a definition used by the frequency administration to provide frequency assignments and assignment of frequency channels to radio stations or systems, as well as to analyze electromagnetic compatibility between radiocommunication services. In accordance with ITU RR (article 1) variations of interference are classified as follows: permissible interference (RR 1.167) accepted interference (RR 1.168) harmful interference (RR 1.169) Conducted interference Conducted EMI is caused by the physical contact of the conductors as opposed to radiated EMI which is caused by induction (without physical contact of the conductors). For lower frequencies, EMI is caused by conduction and, for higher frequencies, by radiation. EMI through the ground wire is also very common in an electrical facility. Susceptibilities of different radio technologies Interference tends to be more troublesome with older radio technologies such as analogue amplitude modulation, which have no way of distinguishing unwanted in-band signals from the intended signal, and the omnidirectional antennas