The IBM 6400 series is a series of four calculating and accounting machines produced by IBM starting in 1962. The IBM 6405 was a desk-size calculator, and the 6410, 6420, and 6430 were more advanced accounting machines. The output for each machine was facilitated a keyboardless IBM Selectric typewriter mounted above the CPU. Programming was done by a control panel. Calculations were done by electronics (SMS) and program steps were controlled by relays. In 1968 an IBM 6430 was developed in Don Mills. The programming was done on cards and the programs steps were controlled by electronics (SMS).