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.
Optional input/output devices included a card reader and punch, a paper tape reader and punch, and a magnetic card reader. The magnetic card reader used a large card (30 cm x 35 cm) with the top part used as a printer ledger. A 2.5 cm 4-track magnetic strip was across the bottom of the card.
The 6405, 6410, and 6420 were developed by IBM in Lexington, Kentucky, United States, in the early 1960s. Manufacturing was done by IBM in Lexington and by IBM in Don Mills, Ontario, Canada. In 1966 all work was transferred to Don Mills.
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).
Production of all models in the 6400 series ended in the early 1970s.