In 1947, US telephone companies began using what?

More Questions:

Klaxon horns were used on what type of vehicle during World War II?

What chain introduced "the Blizzard" in 1985?

What was the original brand of cereal pitched by BuzzBee?

What four US states start with the letter I?

What is the world's largest lake crossed by the equator?

What disorder's name is derived from the Greek for "without appetite"?

What Happy Day's star turned down the plum film role of Danny Zuko in "Grease"?

What was Audrey Hepburn's real last name?

What 2005 movie's tagline is "The longer you wait, the harder it gets"?

What athlete had a part in the movie "Harvard Man"?

What character from a pop song wears a screwed-down hairdo and snow-white tan?

What organisation was given the only Nobel peace prize awarded during World War I?

Who replaced Vyacheslav Molotov as the leader of the Soviet Union in 1941?

In 1967, what company introduced the first consumer model of microwave oven designed for home use?

What were the Crusades?