MITS 816 Desktop Electronic Calcuator

MITS 816 Desktop Electronic Calcuator

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This is one of the first electronic calculators assembled from a kit. In the fall of 1969 H. Edward Roberts, an electrical engineer trained at Oklahoma State University who worked for the U.S. Air Force, founded Micro Instrumentation and Telemetry Systems to build kits for electronic hobbyists. He incorporated the firm in New Mexico in 1970 and moved his focus from building kits for transmitting and receiving measurements over a distance (telemetry) to electronic calculators. Reflecting this shift, he soon shortened the company name to MITS.
In November of 1971, a prototype electronic calculator developed by MITS appeared on the cover of Popular Electronics. MITS hired the journalist and author Forrest M. Mims III to prepare advertising materials and an assembly manual for the production model of the kit. This is the electronic calculator Mims assembled in the course of this work, a MITS 816.
The non-printing calculator has ten digit keys, a decimal key, and a decimal shift key. Left of these are keys for the four arithmetic functions; an equals key; and decimal setting, clear, and clear entry keys. The interior boasts “extra large scale integrated circuitry,” in addition to transistors and other standard electronic parts. Results appear on a row of eight tubes above the keyboard. The power switch is left of the display and a constant switch to the right. A rubber cord extends from the back.
A mark at the center below the display reads: MITS-816. A signature on the bottom reads: ASSEMBLED BY: FORREST M. MIMS, III.
MITS produced other calculators, but dropped out of that business when the price of microprocessors fell sharply. The firm then introduced one of the first microcomputers, the Altair 8800.
Accession File.
MITS, 816, the First and Only Electronic Calculator Kit, 1971.
MITS, Inc., “Offering Circular,” 1973.
Micro instrumentation and Telemetry Systems, Inc. The 816 Electronic Calculator Assembly Instructions, Albuquerque, New Mexico: Micro Instrumentation and Telemetry Systems, 1971.
MITS, 816 Manual, Albuquerque, New Mexico: MITS, 1972.
Currently not on view
Object Name
electronic calculator
date made
Micro Instrumentation and Telemetry Systems
place made
United States: New Mexico, Albuquerque
Physical Description
plastic (overall material)
metal (overall material)
overall: 4 1/2 in x 9 in x 12 1/2 in; 11.43 cm x 22.86 cm x 31.75 cm
ID Number
accession number
catalog number
Credit Line
Gift of Forrest M. Mims, III
See more items in
Medicine and Science: Computers
Computers & Business Machines
Desktop Electronic Calculators
Data Source
National Museum of American History
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The MITS Model 816 was the first kit calculator. Ed Roberts hired me to write the 816 manual, during which I assembled the unit I donated to your collection. Ed and I first planned MITS when we were working together at the Air Force Weapons lab in 1969. Our first product was a model rocket light flasher that I described how to make in Model Rocketry magazine (September 1969). Stan Cagle and Bob Zaller became partners with us from the very beginning. I eventually left MITS to become a freelance science writer, and I wrote the first manual for the Altair 8800 microcomputer, which Ed designed in 1974 and which was featured on the cover of the January 1975 edition of Popular Electronics. Paul Allen and Bill Gates moved to Albuquerque in 1975 to develop Altair software--and found Microsoft.

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