Sperry Remington 661-D & 661
Sperry Remington 661-D
Distinctive features: One of the first of a series of calculators marketed under the Remington name, known for its typewriters and computers.
Display is 6 digits, green fluorescent tubes.
Main integrated circuit - Hitachi HD32154P (date coded 3F 5).
6v (4x AA).
80 mm x 153 mm x 40 mm (3.2" x 6" x 1.6").
Made in Japan.
Although only displaying 6 digits, it calculates to 12 digits. The least significant 6 digits can be transferred to the display by pressing the "Right-arrow" key.
A product announcement for this calculator claimed "Power supply is from four replaceable manganese alkali batteries which will last in continuous use at least 20 hours. A mains adapter is an optional extra." Calculators of this period were power-hungry!
The 661, on the left, was Sperry Remington's first hand-held calculator, though the 661-D was introduced soon afterwards. The 661 has a different case and keyboard design, but otherwise appears to be very similar, though is much less commonly found.
Sperry and Remington had long and varied histories. Sperry Gyroscope Company was incorporated in 1929, and in 1933 Sperry Corporation was incorporated as a holding company of other small firms, including Sperry Gyroscope, Ford Instrument Company, and Intercontinental Aviation, Inc. In 1955 it acquired Remington Rand, a company which was formed in 1927 by combining Remington Typewriter Company, Rand Kardex Bureau, Inc., the Dalton Adding Machine Company, the Safe Cabinet Company, and the Powers Accounting Machine Corporation. Sperry Gyroscope was interested in Remington Rand because of the UNIVAC, the first commerically available computer, which Remington Rand produced and delivered to the U.S. Census Bureau in 1951. In 1986 Sperry Corporation merged with Burroughs Corporation to form Unisys. (Information from the Burroughs Corporation Collection)
There were many calculators which, to save cost, only had a 6-digit display (the Royal Digital III only has a 4-digit display!). Most of these models also have the extra key to reveal the less-significant digits.
© Text & photographs copyright Nigel Tout 2000-2023 except where noted otherwise.