ETSI - EN 300 753
Equipment Engineering (EE); Acoustic noise emitted by telecommunications equipment
|Publication Date:||1 March 2009|
The present document specifies acoustic noise emission limits for equipment used in telecommunication locations as specified in the EN 300 019-1  series. The present document covers switching, transmission, power, supervisory, as well as tariff and billing equipment.
The present document also specifies methods for measuring, reporting and verifying the noise emission of telecommunications equipment. The details of the methods are found in ISO 7779 , ISO 9296  and in the basic standards ISO 3741 , ISO 3744  and ISO 3745 . The descriptor used to quantify acoustic noise emission is the declared A-weighted sound power level in units of bels.
The limits contained herein apply only to the airborne acoustic noise generated by equipment during normal operation. That is, the limits do not apply when operating under emergency conditions or when the equipment is being serviced. Also, the limits do not apply to equipment features which produce sound as an intentional aspect of their operation, e.g. alarm signals, attention signals, speech signals and so on. (For more information on that topic, see ETR 116 ). Furthermore, the present document does not specify maximum sound pressure level limits in specific environments.
Contained within the present document are 6 annexes. Annex A specifies methods for measuring the acoustic noise emitted from equipment manufactured for open air outdoor locations. Annex B contains tables of recommended A-weighted sound power limits for open air outdoor equipment. Annex C discusses the emission of pure tones from equipment. Annex D reviews the motivation for the creation of the present document. Annex E discusses the relationship between sound power and sound pressure. Annex F briefly summarizes the sound power measurement methods used within the present document.