Olivetti Summa 15
Manual, 10/11 digits, Sterling currency
Dimensions: 195W x 350D x 150H
Weight: 7.70kg
Manufactured: Italy, 1949-50s

The Summa 15 is a manually-operated "ten-key" machine with two additional keys for Sterling currency.

Operation is similar to a decimal machine, but with automatic restrictions on the values that can be entered in the pence (first, or rightmost) and ten-shilling (third) columns. Pressing the 10 or 11 keys enters the value and immediately locks the keyboard, so that the current column perforce becomes the rightmost. The third-last place is always the ten-shillings, and will only ever register 0 or 1, regardless of the key pressed. Entering values in the common format of (say) 37/6 will register only 17/6, instead of the expected £1/17/6. A small lever above the keyboard can be set to disable the three Sterling columns, so that the machine will operate in the normal decimal mode on the seven leftmost columns. The single-digit window to the left of the keyboard counts the number of cycles in each place when the machine is set for multiplication mode.

The machine is designed for one-handed operation, with a unique four-way joystick replacing the usual pushbutton function controls. The joystick is easily operated by the right thumb as the hand approaches the main operating handle. The joystick mechanism is described (in English) in US Patent 2545649 (Capellaro, 1949-51).

Manufacturer: Olivetti
Date: 1949

This exhibit has a reference ID of CH5472. Please quote this reference ID in any communication with the Centre for Computing History.

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