International Meridian Conference
On 11 October 1883, a convention of railroad executives met in Chicago and agreed to the implementation of five time zones in North America, using as a basis Greenwich Mean Time. Before the invitations to the Washington conference were sent out on December 1, the joint efforts of Abbe, Fleming and William Frederick Allen, Secretary of the US railways' "General Time Convention" and Managing Editor of the "Travellers' Official Guide to the Railways", had brought the US railway companies to an agreement which led to standard railway time being introduced at noon on 18 November 1883 across the nation. Although this was not legally established until 1918, there was thus a strong sense of "fait accompli" that preceded the Washington conference, although setting local times was not part of the remit of the conference.
Eastern Time Zone
Most cable television and national broadcast networks advertise airing times in Eastern time. National broadcast networks (ABC, CBS, The CW, FOX, NBC) generally have two primary feeds, an eastern feed for Eastern and Central time zones, and a tape-delayed western feed for the Pacific Time Zone. The prime time is set on Eastern and Pacific at 8:00 p.m., with the Central time zone stations receiving the eastern feed at 7:00 p.m. local time. Mountain Time Zone stations receive a separate feed at 7:00 p.m. local time. As Arizona does not observe daylight saving time, during the summer months, it has its own feed at 7:00 p.m. local time. Cable channels with a separate western feed (such as HBO, whose western feed is called "HBOW") generally air the same programming as the eastern feed delayed by three hours. Other cable networks such as the Discovery family of networks repeat their prime time programming three hours later; this allows for the same show to be advertised as airing at "8:00 p.m. E/P" (that is, "8:00 p.m. Eastern and Pacific time"). Networks specializing in the airing of sports events, such as ESPN, advertise all of their programming in Eastern and Pacific, incorporating the 3-hour time difference (as in "8:00 p.m. Eastern/5:00 p.m. Pacific") and leaving viewers in the remaining time zones to calculate start time in their own areas.The Bahamas officially observe both Eastern Standard Time during the winter months and Eastern Daylight Time during the summer months. Cuba generally follows the U.S. with Eastern Standard Time in the winter, and Eastern Daylight Time in the summer, but the exact day of change varies year to year. Cayman Islands and Jamaica use Eastern Standard Time year-round.