Of course, the sending machine and the receiving machines must run in
exact synchronism. This synchronous control of the sending and receiving
motors is maintained by the vibration of a rather heavy fork at each
station, and adjusted to beat together, with such slight automatic
correction by radio as may be required to keep all receiving forks in
step with the fork of the station which at the moment is sending. It is
a very simple and dependable mechanism, by which any number of motors,
of any size, separated by any distance, can be made to run in
synchronism.