The standard settings for these machines required the use of a colon ( on any line considered a "safe" starting point. If this is what you are referring to, it can be turned off on any version I remember looking at.
Although, if you are in a shop where other operators use the machine, you may want to consider whether this should be turned on. It may be convenient for you, but cause a less experienced operator to crash the machine. Especially if everyone else is used to it being set the way it has been for 10+ years.
If you decide you still want to change it, under System Configuration there is a button in the upper left corner (NC Programming, I think). Look under this and you should see a line for requiring a colon to start.