Distinctive features: Desktop calculator from a manufacturer renowned for its small hand-held calculators. Electronics are unusual.
Capabilities: 4 function & memory. Fixed or floating decimal point.
Display: 14 digits, amber gas discharge in 7 modules.
Size: 277 mm x 266 mm x 70 mm (11" x 10.5" x 3"), 1 Kg (2.25 lbs.).
Technology: A calculator chip set with 3 gold and ceramic Large Scale Integrated circuits (LSI ICs) labelled IST 7061, IST 7062A, IST 7063. The ICs were designed by Integrated Systems Technology (IST), though manufactured by a semiconductor foundry, and are here date coded to mid-1972. The circuit board also carries 13 Medium-scale integrated circuits (MSI ICs) and 26 discrete transistors.
The main board is by Varadyne, the display board is by Commodore, and the keyboard by Controls Research Corp.
Probably manufactured in the U.S.A.
This calculator uses the same electronics and display as the Commodore US*14 which is fully described by Rick Bensene at the Old Calculator Museum website at https://www.oldcalculatormuseum.com/us14.html.
The fascinating story of Summit and its hand-held calculators is given in the article "Summit: a Man and the Idea" in the 'Collecting Calculators' section of this site.
With the cover removed showing the circuit board and display.
Close up of the circuit board showing the unusual display and the three ceramic calculator integrated circuits chip set designed by IST on the left.
© Text & photographs copyright Nigel Tout 2000-2023 except where noted otherwise.