decision regarding wholesale rates is still pending. Modernization CN inherited a mixture of switching technologies, some dial exchanges (Whitehorse, Yellowknife, Hay River, Fort Smith), some manual exchanges (Dawson City). Most settlements had no phone service or only one or two lines from a larger centre. Dial telephone service was ubiquitous by the end of the 1960s wherever a local exchange was established. Microwave installations similar to the Alaska Highway route and others in southern Canada replaced outdated or overcrowded pole-line systems on routes paralleling the Yukon's Klondike Highway, and highways in the Northwest Territories, as well as a mammoth pole-line along the Mackenzie River to Inuvik that was only in service from 1968 to 1973. Satellite relays replaced Tropospheric scatterwave systems to DEW-line communities such as Cambridge Bay and Spence Bay, improving signal quality immensely. Manual Mobile Telephone Service, using VHF frequencies, introduced by the Yukon Telephone Company at Whitehorse in the 1950s, was introduced by CNT/Northwestel along all major highways, the Mackenzie River valley and additional off-road regions, during the 1960-1990 period. Further improvements in the 1990s eliminated "double-hop" relays between two satellite-served communities, halving the transmission time for a satellite as much as away over the equator. Nevertheless, bad atmosphere conditions can still skip satellite signals out of the atmosphere for far-north points where the antenna points horizontally across the ground. (The effect is similar when looking at an oar in the water, and the oar appears bent.) Until the 1980s, Northwestel's current operating area (including the Bell Canada area it acquired in 1992) was characterized by north–south communications and transportation links. Airlines flew mainly north–south. Highways such as the Alaska Highway and the Mackenzie Highway were routed north–south. Telecommunication lines and tropo links routed north–south, following the natural transportation corridors. As a result, the area's low requirements were met by long-distance switching as part of southern area codes - 403 in the west and 819 in the east. The Yukon was also covered by 403, not 604, since its lines were handled, prior to Direct Distance Dialing, by operators in Edmonton, Alberta. The northern British Columbia locations, plus Fort Liard, NT until October 1981, were served by area code 604 so that there would be uniformity of dialing codes within that province. Lower Post, BC, linked with the Watson Lake, YT exchange, was covered by 403 prior to 1979. In 1997, the single area code 867 was