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Olivetti Logos 55

Brand: Olivetti.
Model: Logos 55.
Origin: Ivrea, Italy.
Introduction: 1974.
Type: Basic 4-function desktop calculator with internal printer, no display, only AC operation.
Printer: Uses a small rotating print head with 2 rows of 12 characters each. The upper row has the numerals 0 to 9, decimal point and comma, the lower row has special symbols. It uses a standard 75 mm wide paper with an one-color ink ribbon cartridge and prints 20 columns of digits and 2 special columns for symbols. There is a translucid plastic cover to protect the unit.
Keyboard: 25 keys on the main keyboard plus one separate key for Registers Clear (REGS CL), the On/Off switch and two rotating knobs for Round Mode (R/O) and Decimal Point selection (DEC). Also there are two filament lamp indicators: One next to the On/Off switch to indicate the machine is running and one red lamp next to the REGS CL key to indicate an overflow condition. The main keyboard is mechanically very complex: Every key uses small metal moveable pieces to activate seven internal reed switches. Each key generates a different combination on the reed switches, so the calculator can read the "coordinates" of the key depressed. I promise in the future I'll show you this mechanism with more detail.
Main chips: Texas Instruments TMC1828 and two AMI LOG1876 & LOG1878 chips.
Remarks: This calculator was the first of the Logos 50/60 series designed by the italian talent Mario Bellini. Bellini designed other remarkable products for Olivetti like the Programma 101, the Divisumma 18 and the Logos 7. The Logos 55 is in exhibition at the Museum of Modern Art (MoMa) in New York.
Size: 16.8 x 10.1 x 4.8 in, 428 x 257 x 124 mm.
Condition: (8/10) Very Good, minimal marks on casing, full working.
Additional readings: A technical description of the Logos 58 (very similar to the Logos 55) can be read here, from the John Wolff's Web Museum. Also, click here to read about the exhibition of this calculator at the MoMa New York.
Download: Olivetti Logos 55 User Manual (English), in PDF format, click here.


Some advertisements of the Logos 55 (actually of the Logos 68) I found on the web, click on the thumbnail.



Pictures of my Logos 55.


Pictures taken with


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