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The IBM 80 Electric Punched Card Sorting Machine, was introduced by IBM in 1925.
This sorter was almost twice the speed of the older IBM 70 sorter and used an entirely new magnetically operated horizontal sorting design.
At the close of 1943, IBM had 10,200 of these units on rental.
The basic operation of a card sorter is to take a stack of IBM punch cards, examine a single column, and place the card into the corresponding pocket. There are twelve rows on a punch card, and thirteen pockets; one pocket is for "reject" cards.
Cards pass through the sorter the "long way". A single small metal brush is positioned; as each card goes through the machine each spot in a single column passes under the brush in turn. Wherever there is a hole, the brush can make contact with a bit of metal underneath it; when this happens an electric circuit is formed. That circuit in turns directs the card to pass into the correct bin.
To sort several columns, you have pass the cards through several times, moving the brush each time. Sorting is done by first sorting by the least significant digit up to the most significant digit. This is called a "bin sort".
Alphabetical sorting is handled by sorting cards three time on the same column. This also uses another machine adjustment: you can either sort based on the zone rows (the top row is "Y", the next is "X" and the next is "0"; "0" is also a numeric value) or the numeric rows ("9" is as the bottom and "0" is close to the top).
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