The Rotary Machine Switching System, or most commonly known as the Rotary System, was a type of automatic telephone exchange manufactured and used primarily in Europe from the 1910s. Formally named the No. 7-A Machine Switching System, it was developed in Belgium by International Western Electric, a subsidiary of American Telephone and Telegraph (AT&T), at the same time when AT&T's American engineering division, Western Electric, was developing the Panel switch in the United States.