IBM 421

The largely-mechanical IBM 421 read 80-column punch cards and could print upper-case letters of the alphabet, the decimal digits 0 to 9, a period (.

By means of the control panel, any column of the card could be wired to any print column, by means of a wire link (the end terminals of which were manually inserted into slots in the control panel).

After manual wiring, the control panel was inserted in the side of the machine, and a hand-operated lever moved the control panel so that the wire links made contact with corresponding terminals in the machine.

The 421 had 64 positions of memory, typically used to store data from a leading punch card.

A UK 1964-onwards example of commercial use was 421s in multiple South Eastern Electric Board locations calculating and printing the quarterly electricity bill (in pounds, shillings and pence) for each of its thousands of customers after the 421 had read three punched cards for each customer: A 421 could be cable-attached to a "Summary" or "Gang Punch" (IBM 514?)