In a satellite data transmission test performed on October 25, 1962 by IBM, a message was transmitted from an IBM 1401 data processing system in Endicott, N.Y., to an identical computer at the IBM World Trade Corporation laboratory at La Gaude, France. The message was converted by an IBM 1009 Data Transmission Unit from binary coded decimal form into a special transmission code. From this special code serial bits were converted in audio signals in an American Telephone and Telegraph Company digital subset. Those audio signals were then transmitted to the AT&T earth station in Andover, Maine. From there the message was carried by microwave via the Telstar satellite to the earth station in France, and by telephone line to the receiving terminal, where a digital subset reconverted the message into a special code for another IBM 1009, which checked for error and converted to standard binary coded decimal characters for the receiving computer.