The architecture of DC power systems with up to 400VDC ICT equipment interface [ITU-T L.1200] is recommended in [ITU-T L.1201]. This Recommendation is complement to the previous one to give a frame for assessing performances of up to 400VDC power feeding systems and savings compared to other power feeding systems such as -48VDC power system and AC UPS commonly used in ICT sites. This Recommendation deals with performances such as efficiency, reliability/availability, and environmental impact.