When NC machines were originally developed, every manufacturer had their own language for defining part programs. This proved to be problematic, so during the next decade, g-code was developed and standardized for NC and CNC machines.

The history of g-code is long and a little complicated. The Electronics Industry Association’s RS-274 standard was the first attempt at standardizing it. From that evolved NIST’s RS-274NGC. However, just because standards exist, doesn’t mean everyone uses them. There are some controls that are pretty non-standard.

While g-code has been standardized, there are still a variety of dialects used in the machining world. Many manufacturers add a little something extra to their dialect. This is usually for competitive and marketing reasons.

These are the most common differences between dialects:

• Not all controllers support all g-codes
• With g-code mappings, sometimes the same function will be supported by different g-code numbers on different controls
• Parameters and macro programming; because parametric programming with macros came after the basic standards, many controls are limited in their capabilities with it.
• Different controls use different formatting

Having a standard g-code changed the game and made it easier for manufacturers who switched shops. Then, dialects came on the scene, giving machines special capabilities. When a customer purchases a machine from Brooks Associates, they also have the opportunity to receive training to help them fully understand its programming.