Columbia University Computing History   

The IBM 402 and 403 Alphabetical Accounting Machines

IBM 402
The IBM 402 accounting (tabulating) machine, 1948, was an "improved and modernized successor to the 405 accounting machine, the choice of type number notwithstanding" [4]. The 400 series of machines was used to read standard 80-column IBM cards (at speeds of 80 to 150 cards per minute, depending on options), accumulate sums (of positive and/or negative numbers), subtotals, and balances, and to print reports on its integrated printer, all under control of instructions wired into its control panel, that specified which card columns to accumulate in which counters and how to format the report. The 402 rented for $290 per month in 1955.

402 typebars
The 402 series, like the 405 before it, used a typebar print mechanism, in which each column (up to 88, depending on model and options) has its own type bar. Long type bars (on the left in this photo) contain letters and digits; short ones contain only digits (each kind of type bar also includes one or two symbols such as ampersand or asterisk). Type bars shoot up and down independently, positioning the desired character for impact printing. The arrangement of typebars suggests the most common application for these machines: spreadsheet-like columns of numbers, with alphabetic labels for each row on the left.

You can see typebars in action (but on a 405 rather than a 402) in the 1943 film, Air Force, and in the 1944 film, Wing and a Prayer. Typebars were used until the 407 (1949), which was equipped with faster type wheels.

The IBM 403 was identical to the 402 except it could print up to three lines from one card instead of only one. Both used the same control panel, and were smaller cousins of IBM's flagship 407. The IBM 417 and 419 were 402s without alphabetic printing, allowing operation at 150 lines per minute. The 412 was a 402 souped up as a component of the CPC; the 418 was a faster 412 (150 cpm vs 100 cpm). Any of these models could be connected to a Type 513, 514, 517, 519, or 523 Summary Punch, allowing totals accumulated by the accounting machine to be punched to cards for later use:

IBM 403
Type 403 Accounting Machine with Type 514 Summary Punch

IBM 402
Type 403 Accounting Machine with Type 519 Summary Punch

IBM 402 plugboard
Type 402 plugboard



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Columbia University Computing History Frank da Cruz / This page created: January 2001 Last update: 27 March 2021