Why G for G Code?

Why talk about G code when the language actually uses commands designated G, O, F, T M, F and S?

Rumours abound, but the most convincing explanation for those of us old enough to recall the major players of the time, is that the language was used by Gerber Systems Corporation who manufactured photoplotters for the PCB manufacturing industry, way back in the early days. The Gerber file format described the pattern of copper layers, solder masks, printed artwork and drill holes for PCBs.

Gerber used a format of commands to drive their plotters which were 2D numerically controlled (NC) machines.

The Electronic Industries Association defined specification RS-274-D to drive NC machines, and Gerber used a subset of that, which they called Extended Gerber.

Standard gerber was created in the 60s and 70s, so it was around at the beginning of NC and CNC control.

That’;s where the G comes from, or so goes the legend...

You can read more about this here.