order by the Federal Communications Commission required ten-digit dialing of telephone numbers with area codes in the United States that were not overlaid, but had an assignment of the prefix 988 as a central office code, conflicting with its designation for the National Suicide Prevention Lifeline by federal law. NANPA Planning Letter 544 cites 83 area codes affected in 37 states. Three additional area codes were already transitioning to ten-digit dialing as the result of overlay implementations. Central office code 988 was in the process of discontinuation for area code 904. While included in the list of 83 area codes, area code 701 in North Dakota will not be converted to ten-digit dialing because the 32 telephone numbers in the 988 central office were reassigned to another prefix. The implementation schedule determined a permissive dialing period in the affected area codes from April 24, 2021 to October 24, 2021, ahead of the deadline of July 16, 2022, for all calls to 988 to be routed to the lifeline. As part of Canada's implementation of a national 9-8-8 hotline, the Canadian Radio-television and Telecommunications Commission (CRTC) announced in August 2022 that all remaining Canadian non-overlay areas with seven-digit dialing, most of which use "988" as a central office code under their respective area codes, would be required to convert to ten-digit dialing by May 31, 2023. There will be a partial exception for the three northern territories served by area code 867, which is not projected to exhaust until at least 2043; only the Yellowknife area (which contains the 988 exchange) will be required to convert, with seven-digit dialing remaining optional elsewhere in the region due in part to unique geographical and cultural considerations. See also List of country calling codes Telephone numbering plan References External links NANPA report of NPAs requiring ten-digit dialing North American Numbering Plan