"19-inch design" (19'') is the common name for a standardized

Modular system for electronic devices and plant components. The individual components are dimensioned in such a way that they can be easily combined and exchanged. The series of standards in which this design is defined is DIN 41494 and describes, expressed in SI dimensions, the 482.6mm design (482.6 = 19").

 

This standard dimension of 19" for the front panel width spread from the USA to Europe after World War II. Because electronic devices from Europe and the USA were being combined more and more frequently, standardization based on the 19" front panel began in Germany.

 

At the beginning of the national standardization work, an attempt was made to merge the various existing standards into one set of standards, since in addition to the 19" specification, there are also, for example, standardized printed circuit board formats with metric external dimensions. This resulted in a structure of the entire design in four levels almost automatically each higher level accommodates the structural units of the lower level.All in all, this system means enormous advantages for the electronic device or system in terms of development, repair, maintenance, logistics and flexible change or expansion of the functions.

 

The standardization had to meet contradictory requirements: on the one hand, the system components had to be as completely interchangeable as possible, and on the other hand, freedom of construction and design, without which further development and technical progress are not possible. This difficult task was solved by sensibly structuring the construction method and by precisely determining the dimensions of the resulting interfaces.

 

However, since not all individual parts are standardized down to the smallest detail due to the freedom of design, unrestricted interchangeability is not given.

 

But it is precisely this balance of definition and freedom that has made this type of construction so successful. It is used in almost all areas of electronics internationally, with the only exception being consumer electronics with its large quantities per device. Electronic devices and systems are advantageously constructed in a modular manner, since they offer economic and technical advantages in this way. This begins with project planning and development, continues with production and testing and ends with commissioning and service. The modular structure of the 19" design can be divided into four levels.