This 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 (ST) 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 61000-6-4 will meet the emission
requirements of this standard provided that emissions from any d.c. power port are within the
emissions limits specified for a.c. power ports. The immunity levels of EN 61000-6-2 will also be
adequate except for the special case of apparatus as defined in note 1 of Table 1. 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.
If a port is intended to transmit or receive for the purpose of radio communication (intentional radiators.
e.g. transponder systems), then the emission and immunity limits in this standard at the
communication frequency do not apply.
The standard does not specify basic personal safety requirements for apparatus such as protection
against electric shock, unsafe operation, insulation co-ordination and related dielectric tests. The
requirements were developed for and are applicable to this set of apparatus when operating under
normal conditions. Fault conditions of the apparatus have not been taken into account.
The requirements and test methods also apply to telecommunications and signalling data and power
lines connected to the equipment under test (EUT).
The frequency range considered is from d.c. to 400 GHz. No measurements need to be performed at
frequencies where no requirement is specified.
For products in the scope of EN 61000-3-2 or EN 61000-3-3, the requirements of those standards
apply.
Testing methods are given in the basic standards listed in Clause 2, Normative references.
These specific provisions are to be used in conjunction with the general provisions in EN 50121-1.
NOTE The immunity and emission levels do not of themselves guarantee that the integration of apparatus will necessarily be satisfactory. The standard cannot cover all the possible configurations of the apparatus, but the test levels are sufficient to achieve satisfactory EMC in the majority of cases.

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• DS DS/EN 50121-2 : Railway applications - Electromagnetic compatibility - Part 2: Emission of the whole railway system to the outside world

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