At least two microcomputers are provided for the controlling operation of an automatic vending machine, which are connected by signal wires of a number selected from one to four with respect to each other. One of the microcomputers is a main microcomputer, while the other thereof is a submicrocomputer....http://www.google.fr/patents/US4598379?utm_source=gb-gplus-shareBrevet US4598379 - Control system of an automatic vending machine
