Some cities could not yet be included in DDD as they did not yet have the necessary toll switching equipment to handle incoming calls automatically, or because they still did not use a local seven-digit numbering system. Montreal, Quebec and Toronto, Ontario in Canada, for example, had a mix of six- and seven-digit numbers from 1951 to 1957, and did not have DDD until 1958. Whitehorse, Yukon had seven-digit numbers from 1965, but the necessary switching equipment was not in place locally until 1972.