scope:

This European Standard applies to signalling and telecommunication apparatus which is installed in the railway environment. Signalling and telecommunication apparatus mounted in vehicles is covered by EN 50121-3-2. This Standard specifies limits for emission and immunity and provides performance criteria for signalling and telecommunications (S&T) apparatus which may interfere with other apparatus in the railway environment, or increase the total emissions for the railway environment beyond the limits defined in the appropriate standard, and so risk causing Electro-magnetic Interference (EMI) to apparatus outside the railway system . Apparatus which complies with the emission levels of EN 50081-2 will meet the emission requiremetns of this standard provided that emissions from any d.c. power port are within the adequate except for the special case of apparatus installed close to the rails. This standard provides the immunity requirements for such apparatus. The immunity levels given for the apparatus will in most cases allow the apparatus to perform as intended in the railway environment (see note). The immunity level establishes a common reference for evaluating the performance of the apparatus when subject to interference resulting from direct exposure of the apparatus and associated cables to a radio frequency field, or by coupling of the interference from a remote source.