Unisonic 1040-C Handheld Electronic Calculator

Electronic calculators were frequently advertised in March and April as aids to Americans computing personal income taxes. Federal taxes on personal income had been legalized in the United States by the passage of the Sixteenth Amendment to the U.S. Constitution in 1913. A form for calculating these taxes known as the 1040 was introduced soon thereafter, and was widely known by American workers by the 1970s. Hence the name of this calculator.

The handheld electronic calculator has a metal and plastic case with an array of twenty-five rectangular plastic keys. These include ten digit keys, a decimal point key, a total key, four arithmetic function keys, four memory keys, a square root key, a percentage key, a change sign key, an exchange key, and a clear/clear entry key. The keys are similar to those on the Unisonic 1040, although they are arranged slightly differently and the clear and clear entry key have been combined. Above these keys is an on/off switch. A mark left of this reads: Unisonic 1040. Behind this is an eight-digit green fluorescent display.

A power jack is along the back edge.

A sticker on the back gives calculation examples. A mark on it reads: 1040-C. Another mark reads: SERIAL NO. (/) 256086 (/) MADE IN JAPAN. Below this is a compartment for four AAA batteries.

Compare five examples of the Unisonic 1040: 1986.0988.110 (the 1040), 1986.0988.291 (the 1040-1), 1986.0988.292 (the 1040-AT), 1986.0988.109 (the 1040-C), and 1986.0988.108 (the 1040-C). The keys are not identical.

References:

For a timeline of historical events relating to personal income taxes, see the website of the Internal Revenue Service at www.irs.gov.

[Advertisement], Morning Herald [from Hagerstown, Maryland], November 28, 1975, p. 49. Selling Unisonic 1040 for $22.96.

[Advertisement], Chicago Tribune, September 1, 1977; p. I2. Unisonic 1040 selling for $10.96, regularly $13.96.

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