Depending on where you live in the country, Okuma distributors use different G-code macros for tool changes. Both macros accomplish the same thing; reduce the amount of errors during operation and the amount of key strokes needed to do simple tool changes. If you just use M6 T#, and also pre-stage tools with a T# on a following line, you will get an alarm during restarts when the control reads the M6 again. This requires you to use M64 to un-prep the staged tool, then restart again. If you want to clear the spindle, you normally have to issue an M63 then M6. If you have a prepped tool but want to change to a different tool number, you would normally have to use M64 to unprep the current tool, then M6 T# to call the new tool.
G111 and G116 are custom macros that handle situations like this and makes it easier on the operators to use.
To answer the original question, if you put a T# on any line after your M6 the machine will prep the T# for a faster tool change.
