Electromagnetic Interference (EMI) or Radio-Frequency Interference (RFI) can be described as any form of electrical disturbance signal or noise generated by electronic devices may negatively affect other electronic devices, and is active throughout the environment. Its effects vary from impaired TV or radio reception to severe disruption of communications, data processing and medical and defense activities. Its sources are both natural and man-made. EMI and RFI may cause malfunctions in electronic devices. Specifically, EMI and RFI cause suppression of signals generated internally in a device, or equipment. Therefore, EMI and RFI are potential problems in any industry.

Many companies establish their own specifications for immunity to EMI over a range of phenomena. These may include electrostatic discharge (ESD), radiated immunity, and electricfast transients (EFT), etc. It is also necessary to contain emitted signals from computer and data handling equipment to prevent electronic eavesdropping for example, where these signals may interfere with other sensitive electronic equipment in the nearby vicinity. The simplest way to achieve this is by the Faraday Cage Principle and in effect, this is what happens in most cases (metal frames or casings placed over the source of the emission).

EMI/RFI shielded windows are an extension of this principle in that the fine wire mesh acts as a barrier to these emissions but at the same time allowing the operator sight of the display into, or out of the shielded room or area. The windows on their own will not solve RFI problems but must be an integral part of a fully shielded system.

In order to prevent EMI or RFI, EMI/RFI Shielding agents may be used as protection. In most cases, EMI/RFI Shielding is in the form of a spray. The spray is often acrylic based, and is applied to plastic electronics housings. Highly pure metals such as nickel, silver, and copper in the spray help to reduce or completely eliminate EMI and RFI interference. EMI/RFI Shielding agents are also available as paints and brush on coatings.

Electromagnetic shielding solutions are available meeting specific EMC, CE, FCC, TEMPEST or MIL-STD 461 standards for the electronic, medical, space/defense industries, and secure areas such as computer rooms, RFI/EMI testing chambers, buildings, airport terminals, rail terminals, bus terminals, telecommunication racks, test and measurement equipment, navigation equipment, medical equipment, radar applications, communication systems, hand-held computers, secure laptop computers, etc.