Equipment Engineering (EE); Power Supply Interface at the Input to Telecommunications Equipment; Part 1: Operated by Alternating Current (ac) Derived from Direct Current (dc) Sources
"This European Telecommunication Standard (ETS) contains requirements for: - the output performance of the (stabilized) ac power supply derived from dc sources as specified in ETS 300 132-2 [9]; and - the input of the telecommunications equipment connected to interface ""A""@ powered by ac not directly provided by the mains. This ETS also makes reference to safety and EMC standards which are in accordance with the relevant European and international standards. This ETS aims at providing compatibility between the power supply equipment and the power consuming telecommunications equipment@ and also between different load units connected to the same power supply. NOTE 1: To ensure satisfactory performance@ the connection of telecommunications equipment into installations is subject to the prevailing conditions of that installation and is subject to the agreement of both parties. NOTE 2: For dc power supply systems operated at a nominal voltage of -48 Vdc@ ETS 300 132-2 is available. The power supply interface@ interface ""A"" of figure 1@ is a physical point to which all the requirements are related. This point is situated between the power supply system(s) and the power consuming telecommunications equipment. NOTE 3: Interface ""A"" is located at the power terminals of the telecommunications equipment. Subject to the installation preconditions@ this point may be located at any other point between the power supply system and the telecommunications equipment by mutual agreement of both parties. The requirements at interface ""A"" apply to: - the output of the power supply equipment or power supply installation of telecommunications centres; - the power supply input of telecommunications equipment installed at telecommunication centres; - telecommunications equipment@ installed in customers' premises@ whose power interface ""A"" is also used by equipment requiring a supply to this specification. NOTE 4: Normally there is more than one load unit connected to interface ""A"". In some of these cases interface ""A"" might undergo further restrictions with respect to noise limits or other disturbances. NOTE 5: This ETS also gives requirements on disturbances on the power supply interface ""A"". However@ continuous wave phenomena above 20 kHz are not covered within this ETS. ETS 300 386-1 [8] is applicable for this frequency range. NOTE 6: The transients to which immunity is specified in this ETS are characterized by a high energy content such that electrical stress may be caused. Fast transients@ the effects of which appear mainly as interference@ are covered by ETS 300 386-1 [8]. NOTE 7: An example of a configuration in which the interface ""A"" is identified is given in annex C. The purpose of this ETS is: - to enable the use of a power supply system with the same characteristics for all telecommunications equipment defined in the area of application; - to facilitate interworking of different (types of) load units; - to facilitate the standardization of telecommunications equipment; - to facilitate the installation@ operation and maintenance in the same network of equipment and telecommunications systems from different origins."