Sumlock Comptometer 993S Model 912/VZ/S/918.174
Manufactured by the Bell Punch company Limited and distributed in the UK by Sumlock Comptometer Ltd
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.
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.
This Comptometer was very kindly donated by Elsie Bennett and is in an excellent working condition
This exhibit has a reference ID of CH29894. Please quote this reference ID in any communication with the Centre for Computing History.