As mentioned in a previous post, G-Code is the standard machine tool language around the world; generally consists of specifying the X/Y/Z (and A/B/C) coordinates that the machine is to move to. Movements can be linear, circular, or even special drilling operations. G-code is the universal language of all modern machine tools including CNC.
M-Code is also a CNC programming language including standard machine tool codes that are normally used to switch on the spindle, coolant, or auxiliary devices. They can also be used for G-code program control such as repeating the program or ending it.
MultiCam’s website has dedicated a section explaining G & M code. To access the page, click here.