Your understanding is correct, however it should be borne in mind that the restriction classes can be modified, but that is another matter.
Manuals can be found here.....
http://www.neccare.com/cng/docs.nsf/Lib3?OpenView Under the NEAX2000/Neax1000 heading then select your system type then you want the Command manual. I would also recommend the feature programming guide for newbies as well. There is also a feature description manual which can clarify what you are trying to achieve.
Another area worth a visit for tutorials is here......
http://www.tek-tips.com/faq.cfm?pid=937 Hope this helps.