Okuma LC-40 G20 and G21 description

Hey guys
Just started training on an Okuma LC-40 with an OSP 5000 controller.
I was looking for an easy way to make the tool holders go to tool change positions, and i find a reference to a G20 and G21 conde from the list on this page: Okuma Lathe G M codes G-codes M-codes

But I can't seem to find any more info on those.
I've been searching through the manuals for the better part of the day with nothing to show for it.
Does anyone know of them?

Those I believe are for the later model machines with ATC's. You dont have an ATC.

Is there any other code I can useto make them goto tool change positions?

G0 X100Z100

Cogsman1 is right. Any command that you rapid to that is greater than the positive X or Z limit will be OK for a tool change. (it looks for positive limit to allow indexing) ATC machines did use Home positions, but you don't have that, right?

Best regards,