ETSI EN 300 132‑2 Compliance Testing
Telecommunication equipment is being widely used in everyday life. The undesired electromagnetic noise emissions from this equipment could interfere with the signals in other communication equipment in the vicinity. When the noise is in the audio range of 25 Hz to 20 kHz, it may also affect the quality of signal transmissions in telephone lines. In audio systems, this undesired audible noise can be in the form of hissing, humming and other sound disturbances.