If you’re having trouble dialing 9 to get an outside line to dial with on a Nortel phone system, then you may have two or more Line Pools setup on the system.
Is there more than one company at your place of business? Do different departments have their own pool of special phone numbers that only they can use?
Phone sets can be configured to have access to more than one Line Pool, but if they only have one then you’ll need that “access code”. In my case, the code for that company was 8, while the rest of the building dials 9 for an outside line.