This part of IEC 61204 specifies electromagnetic compatibility (EMC) requirements for power supply units (PSUs) providing d.c. output(s) with or without auxiliary a.c. output(s), operating from a.c. or d.c. source voltages up to 600 V a.c. or 1 000 V d.c. (see exceptions under 1.1.3.) NOTE Ringing generators used in telecoms applications are covered by this standard. This product standard covers both stand alone and component power supply units as defined in this standard. It covers PSU units for use in or with IT equipment normally covered by IEC 60950-1 and/or IEC 62368-1; PSU units for use in or with measurement, control and laboratory equipment normally covered by IEC 61010-1; PSU units for use in or with medical equipment normally covered by IEC 60601-1; PSU units for use in or with audio, video and similar electronic apparatus normally covered by IEC 60065 and/or IEC 62368-1. It also covers d.c. power and distribution equipment and d.c./d.c. converters. Where no standard exist, use of this standard for other applications is not precluded.