The first implementation of a numerical control programming language was developed at the
MIT Servomechanisms Laboratory in the 1950s. In the decades that followed, many implementations were developed by numerous organizations, both commercial and noncommercial. Elements of G-code had often been used in these implementations. The first
standardized version of G-code used in the United States,
RS-274, was published in 1963 by the
Electronic Industries Alliance (EIA; then known as Electronic Industries Association). In 1974, EIA approved
RS-274-C, which merged
RS-273 (variable block for positioning and straight cut) and
RS-274-B (variable block for contouring and contouring/positioning). A final revision of
RS-274 was approved in 1979, as
RS-274-D. In other countries, the standard
ISO 6983 (finalized in 1982) is often used, but many European countries use other standards. For example,
DIN 66025 is used in Germany, and PN-73M-55256 and PN-93/M-55251 were formerly used in Poland. From the 1970s to 1990s, many CNC machine tool builders attempted to overcome compatibility difficulties by standardizing on machine tool controllers built by
Fanuc.
Siemens was another market dominator in CNC controls, especially in Europe. In the 2010s, controller differences and incompatibility were mitigated with the widespread adoption of
CAD/
CAM applications that could output the appropriate G-code to operate a specific machine through a software tool called a
post-processor (sometimes shortened to "post"). == Syntax ==