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Not all numbers that begin with 555 are fictional—for example, 555-1212 is one of the standard numbers for directory assistance throughout the United States and Canada. In fact, only 555-0100 through 555-0199 are now specifically reserved for fictional use - except for the 800 area code where only 800-555-0199 is reserved - the other numbers have been released for actual assignment. The entire 555 exchange is reserved in all overlay North American toll-free area codes (844, 855, 866, 877, 888)[1] and in Canada's rarely-used non-geographic area code 600.
Area code 555 in the North American Numbering Plan is reserved for Directory Assistance applications.