Sumlock Comptometer 993S Model 912/VZ/S/933.896.

A 10-decade, decimal Comptometer, electrically driven, with storage (memory).

Model number 912/VZ/S/933.896.
346 x 324 mm x 200 mm (13.5" x 12.75" x 8").

Made in Great Britain by Bell Punch Company Ltd.
Bell Punch acquired the right to use the name "Comptometer" from the U.S. Comptometer Corporation in 1960.

This machine has the standard full keyboard with 12 decades of keys (1 to 9). As usual on Comptometers, pressing a key adds that number to the accumulator register, as shown in the lower row of windows, here showing 12300000.

Pressing the + side of the rocker switch on the right adds the contents of the accumulator register to the storage register (memory) along the top, here showing 24600000. Pressing the "-" side of the rocker switch subtracts the accumulator contents from the storage register.

The clearing switch at lower right can individually clear the accumulator or the storage registers.

Our thanks to for the use of the cutaway pictures

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This exhibit has a reference ID of CH1315. Please quote this reference ID in any communication with the Centre for Computing History.

Sumlock Comptometer 993S Model 912/VZ/S/933.896.

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