UNE-EN 60917-2-3
Modular order for the development of mechanical structures for electronic equipment practices - Part 2-3: Sectional specification - Interface co-ordination dimensions for the 25 mm equipment practice - Extended detail specification - Dimensions for subracks, chassis, backplanes, front panels and plug-in units (IEC 60917-2-3:2006). (Endorsed by AENOR in September of 2006.)