The computer in NORAD is made up from components of an actual IBM AN/FSQ-7 Combat Direction Central, built in 1954 to protect the US from Soviet bomber attack. Components of decommissioned systems were sold for scrap and bought by film and television production companies that wanted futuristic-looking computers, despite the fact they were built in the 1950s. Components used in this film were previously used in The Time Tunnel (1966), The Towering Inferno (1974) and WarGames (1983), among many others, and later used in Fail Safe (2000).
When practicing their bombing run on Irkutsk, they simulate flying over the city at heading 230, and Cassidy (Powers Boothe) quips "Right down Karl Marx Street". This is rather accurate; Irkutsk does have a Karl Marx Street, and its heading - when going to the south west - is nearly 230. They would slowly be crossing it from left to right.
Final film to depict a fictional World War III prior to the end of the Cold War and the collapse of the USSR (Union of Soviet Socialist Republics aka the Soviet Union aka Russia). The Matte World Digital websites states: "By Dawn's Early Light (1990), produced in the 1980's, was the last of the 'what if the weapons get loose' cold war suspense thrillers released before the fall of the Soviet Union."
The differences between this television adaptation and its source novel are summarised by the Wikipedia website which states that there are two major differences between the story of its source novel and this filmed tele-movie adaptation. It says: "The first being that the crisis in the novel is started by a deliberate Soviet attack to counter the US military buildup with which they are unable to compete" and "the other major difference in the film is in the romantic subplot between Moreau [Rebecca De Mornay] and Cassidy [Powers Boothe], which is absent from the book, the characters themselves actually mocking the idea of such a relationship between them".
The five levels of alert status / alert code, in ascending order of urgency, were: "Apple Jack", "Snow Man", "Cocked Pistol", "Round House", and "Big Noise". These alert status are training status only.