Well, thanks for the help and information. I think I have it figured out. What I have learned here plus my own experiments and a whole day of head scratching has led me to this:
COR Groups
A COR Group is just a list of numbers assigned by the user.
COR classes
There is no such thing as a list of CORs and there is no COR form. A COR exists because it appears in a COR Group.
ARS
An ARS route contains a COR Group entry, assigned by the user, which points to an entry in the table of COR Groups. A COR Group linked to a route in this way controls access to any route that links to it.
Station Attributes
Each station attributes record contains a COR entry for each of the three time periods Day, Night 1, and Night 2.
If the COR Group linked from a route in the ARS Route table contains the originating station’s COR, the route will be blocked for that station.
other
Simply creating a group containing “1-64” and entering that group in the COR for a station absolutely will not, by itself, block all outside calling.
There is no such thing as a COR form. There is only the COR Groups form, the link to its contents from ARS Routes, and the reference to it in Station Attributes.
Restrictions for digits dialed is strictly a matter for the ARS Route configuration.
Once again, thanks to everyone for the help.