Communications infrastructure equipment employs a variety of power system components. Power factor corrected (PFC) AC/DC power supplies with load sharing and redundancy (N+1) at the front-end feed dense, high efficiency DC/DC modules and point-of-load converters on the back-end. Communication station power supply also includes guaranteed building loads that allow. Computer room commonly used power supply uninterruptible power supply (UPS) power supply, due to the use of pulse width frequency modulation technology, the maturity of high-efficiency power devices, microprocessor development and other factors, the uninterruptible power supply has become the main. Communication DC power supply system mainly includes switching DC power supply system and linear DC power supply system. Switching DC power supply system utilizes the switching characteristics of the switching device, through the high frequency conversion and filtering, the alternating current is. This document provides a specification of the Norwegian HE sector's recommended requirements for power supply for ICT rooms. The document is a revision of version 3, dated 22 December 2009.