Object Details
maker
Texas Instruments
Description
In 1972 Texas Instruments began selling electronic calculators under its own name. The first of these was the Datamath or TI-2500. Over the next few years, TI sold modifications of the TI-2500 that had different forms of battery (such as the TI-2500B, the TI-2500II, the TI-2510, and the TI-2550III), a different color case (the TI-2510 and the TI-2550III), a key for taking percentages (the TI-2550, the TI-2550II, and the TI-2550III), and keys for additional functions (the TI-2550, the TI-2550II and the TI-2550III). This is an example of the TI-2550III.
The calculator has an array of thirty-five rectangular plastic keys. These include ten digit keys, four arithmetic function keys, a clear key, a clear entry key, a decimal point key, and a total key. Also included are a change sign key, a percentage key, four memory keys, an inverse key, a square key, a square root key, and a reverse entry (RV) key. The RV key replaced an entry in the display with the immediately preceding entry.
The on/off switch is above the keyboard on the right. A mark above it reads: TEXAS INSTRUMENTS TI-2550III. Behind this is an eight-digit blue vacuum fluorescent display.
There is a jack for a power adapter along the back edge (according to instructions for the calculator found online, this would have part number AC9310A). The back has a battery compartment that would hold a rechargeable battery pack (according to instructions for the calculator, this would have model number BP-3).
A sticker on the back of the calculator reads in part: US PAT 3819921 OTHER PATENTS PENDING (/) TEXAS INSTRUMENTS (/) TI-2550-III (/) electronic Calculator (/) Serial No. (/) 2550-III 075877. It also reads in part: ASSEMBLED IN USA. A mark below the label reads: 4576LTA.
Unscrewing four screws from the back of the calculator reveals the circuit board. The largest chip is marked: TMS1043NL (/) KBSΔ7642.
The calculator has a black plastic zippered case.
References:
[Advertisement], Boston Globe, November 25, 1976, p. 92. Selling for $29.95.
[Advertisement], Los Angeles Times, January 29, 1977, p. C5. Advertised as selling for $28.95.
Guy Ball and Bruce Flamm, The Complete Collector’s Guide to Pocket Calculators, Tustin, CA: Wilson/Barnett, 1997, p. 158. They give a 1976 price of $34.95.
Online Datamath Museum.
Location
Currently not on view
Credit Line
Gift of John B. Priser
date made
1976
ID Number
1986.0988.347
catalog number
1986.0988.347
accession number
1986.0988
Object Name
electronic calculator
Physical Description
plastic (case; keys; carrying case material)
metal (circuitry; zipper material)
paper (sticker material)
Measurements
overall: 1 1/4 in x 3 in x 5 3/4 in; 3.175 cm x 7.62 cm x 14.605 cm
See more items in
Medicine and Science: Computers
Computers & Business Machines
Handheld Electronic Calculators
Data Source
National Museum of American History
Link to Original Record
Record ID
nmah_1364041