The M700 code allows programs to trigger notifications to the user. Currently, it only provides a way to indicate which tool should be loaded by the user. Post processors can use this before a program pause (M0 or M1), to indicate to the user which tool they should load. M700 accepts the T to specify which tool should be shown in the notification.
Example:
M700 T1 M0 M6 T1 G43
The snippet above will prompt the user with the message “Load tool 1, then press cycle/start.”. It then pauses the program, which allows the user to manually load tool 1 before pressing cycle/start to proceed.