BTM vertical sorter, 1911.
© Science Museum / Science & Society Picture Library
The function of the sorter was to arrange punched cards in the order required for the tabulator. The cards were fed one at a time into a mechanism which sensed the position of a hole in a particular column. As the card then moved along the machine, the correct shutter would open directing the card into a receiver box below. Electronic systems of tabulation were cheaper and more efficient than manual systems and were originally used for procesing census information. This vertical sorter was made by the British Tabulating Machine Company.