In the original North American Numbering Plan, phone numbers beginning with an area code of "800" were reserved for so called toll-free numbers, where the party receiving the call pays the charges. As more toll-free numbers were needed, additional area codes were added to the scheme including 888, 877, 866, and four more were reserved: 8555, 8444, 8333 and 8222. The term "800 Number" is used colloquially to refer to all of these.