Electromechanical distributor for sorting mail

One unit of the system comprises 4 operating desks, to which letters are automatically fed, together with a distributor. Each letter is held before the operator long enough for a 3-number code to be punched on a keyboard. The letter then passes to one of an endless chain of boxes from which it is released when the box passes the proper destination case. The electromechanical memory is similar to that used in telephone practice: circuit details are not given, but the main mechanical and electrical features are described.