M00
From CNC.xyz Wiki
This is known as the Program stop M-Command known as M00. This command is useful to be run whenever a stop is desired. The machine will pause in its place until a start command is given by the machine control software. Sometimes also known as a 'Feed Hold'.
Once a M00 command has been triggered, typically the only way to resume the program is for the operator to enter a Cycle Start command using the CNC Control Software. The program will resume on the following line.
Standard Format: M00
There are no additional parameters required to execute this command.
Code Examples
In this example, the program stop will be executed.
... M00