English: Evoloution of Area Codes 867 and related.;1947–1957: No places in Canada had DDD, therefore all area codes are shown in italics. The area codes were mainly used as operator references to reach other operators ("inward") to complete calls. Only Whitehorse had an exchange with long distance connections; the only other exchanges in the Yukon were in Mayo and Dawson, which were not connected to long distance.

1957–1962

Some places in the depicted sections of the 604, 403, 306 and 204 area codes had DDD. No places in the depicted portions of 705, 819 and 418 had DDD. The red squares in the territories mark existing exchanges that were connected to long distance by the end of 1962.

1962–late 1970s

All provincial area codes had DDD locations, although the portion of 418 shown had no DDD locations. Some non-DDD locations (red squares) in the Yukon and southern NWT are not shown among the blue dots of DDD locations. DDD is not known to have been available in Frobisher Bay prior to the implementation of Area Code 819 in the eastern NWT, but it is possible it was available, and incoming calls were dialed 1-418-979-xxxx.

late 1970s–1996

All Yukon locations had DDD by April 1980. All NWT locations served by Northwestel had DDD by March 1980, except for Port Radium (turned off, late 1982), Wrigley (received late 1981), Fort Liard (received late 1981). Availability of DDD for Bell Canada locations is not known, but was completely available by 1992. Exchanges in the depicted area of 418 all obtained DDD during the period of this map; possibly the only such locations are Fermont and Schefferville.

1997–present

Exchange locations are no longer shown because DDD is completely available.