This Official Mexican Standard also applies to external power supplies, which are used in conjunction with the electronic equipment contemplated in this Official Mexican Standard, which are marketed, distributed or supplied, either individually or as part of a product of final use in the same packaging, and to external power supplies that are marketed individually for information technology equipment contemplated in the field of application of NOM-019-SCFI-1998 or that replaces it, in both cases for use in DC power supplies up to 250 V and in AC power supplies up to 480 V at 60 Hz.