Texas Instruments TI-2500 II (Datamath II) Handheld Electronic Calculator

Description
This is an example of an early handheld electronic calculator marketed by Texas Instruments under its own name. The calculator has a tan plastic case with a dark brown keyboard. It has an array of nineteen keys, seventeen of them square and two rectangular. These include ten digit keys, a decimal point key, a total key, four arithmetic function keys, a clear key, a clear entry key, and a percentage key. The percentage key distinguishes it from the TI-2500B.
A mark above keyboard on the right reads: Datamath II. Behind the keyboard is an eight-digit LED display.
A jack for a power adapter is along the back edge. An on/off switch is on the left side.
The back of the calculator has a compartment for storing either two rechargeable nickel-cadmium batteries or two AA-sized non-rechargeable batteries.
A sticker on the compartment cover reads: TI-2500II electronic calculator (/) Texas Instruments Incorporated (/) P.O. Box 22288: Dallas, Texas 75222. It also reads in part: Serial Number (/) 2500II- 019756. The sticker indicates that the calculator should be recharged for twelve hours using an AC9130 adapter/charger.
Unscrewing three long screws on the back of the case does not reveal the chips.
This modification of the TI-2500 was introduced in 1974 and sold at least until 1975.
Compare 1986.0988.188, 1986.0988.189, 1986.0988.190, 1986.0988.342, and 1986.0988.359.
References:
Guy Ball and Bruce Flamm, The Complete Collector’s Guide to Pocket Calculators, Tustin, CA: Wilson/Barnett, 1997, p. 157.
Online Datamath Museum, accessed May 13, 2015.
[Advertisement], Chicago Tribune, March 2, 1975, p. G27. Price given as $49.95.
Location
Currently not on view
Object Name
electronic calculator
date made
1974-1975
maker
Texas Instruments
Physical Description
plastic (overall material)
Measurements
overall: 1 5/8 in x 3 7/8 in x 5 1/2 in; 4.1275 cm x 9.8425 cm x 13.97 cm
ID Number
1986.0988.342
catalog number
1986.0988.342
accession number
1986.0988
See more items in
Medicine and Science: Computers
Handheld Electronic Calculators
Computers & Business Machines
Data Source
National Museum of American History, Kenneth E. Behring Center

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