In [[telephony]], especially in [[NANP|North America]], a '''split plan''' is the practice of introducing a new [[area code]] by dividing an existing area code's territory and applying the new area code to one of the resulting divisions, replacing the existing area code within that section.
Split plans becamewere increasinglyused unpopular throughin the 1980s and 1990s, as growth in demand for telephone numbers grew to require new area codes in increasingly densely populated areas (due to the increase in use of pagers, fax machines, and cellular phones.) Muchrequired ofnew thearea resistancecodes resultsin increasingly densely populated areas. Unpopularity resulted from the fact that, after a split plan iswas implemented, the telephone numbers in thean affected area arewere changed to thea new area code, requiring printing of new [[stationery]], advertisement, and signage, and the dissemination of the new numbernumbers to family, friends, and customers (both existing and potential).
As a result of this resistance, in the mid 1990s, the [[North American Numbering Plan]] introduced [[overlay plan]]s, which apply multiple area codes to the same area. ThisThey allowsallow customers to keep existing phone numbers, but requiresrequire [[10-digit dialing]] in the affected area.
