Hewlett-Packard HP-41X Handheld Electronic Calculator, Engineering Model

This is an engineering prototype for an improved form of the HP-41CX, one of the first forms of an Hewlett-Packard handheld electronic calculator that could show letters as well as numbers in the display. The HP-41 series included the HP-41C (introduced 1979 – code name coconut), the HP-41CV (introduced in late 1980), and the HP-41CX (introduced in 1983). In the course of the 1980s, Hewlett-Packard engineers devised a way of building the calculators with fewer chips that cut the cost in half and improved reliability. These were codenamed “halfnut” calculators. This is a model for the “halfnut” version of the HP-41CX, made in about 1985.
The prototype has a translucent plastic case, and four rubber feet. A plastic template covers the keyboard. This keypad is marked with the functions of the calculator in orange, white, and blue. A latch just below the display releases the template. Under the template are thirty-five plastic keys, marked in white and blue. The calculator lacks the usual keyboard under the keys, having a transparent one instead.
Four buttons behind the keys are for turning on the machine, setting user determined key functions, setting programming mode, and setting alphabetic mode. Behind this is the LCD display.
The top edge has four slots for additional memory or devices. One of these is empty, one of them has a chip encased in plastic, and two of them have plastic frames but no circuitry. The chip enclosed in plastic is a prototype for an infrared “blinkie” transmitter linking the calculator to a printer. Such a transmitter originally was envisioned for calculators in the HP-28 series, but a Hewlett-Packard engineer suggested that HP-41 calculators also could link to the printer.
A mark along the front edge of the calculator reads: hp HEWLETT • PACKARD 41CX. Text at the top of the back reads: SERIAL NO. However, there is no serial number.
The donor of this model, David Rabinowitz, was an employee of Hewlett-Packard from 1975 until 1989 and worked on the design of the halfnut form of the HP41CX calculator as well as on HP’s infrared printers.
The 41C and 41CV sold until 1990, the 41CX until 1991. (another source (http://www.hpmuseum.org/hp41.htm) gives dates of discontinuation of 1985 for the HP-41C, 1990 for the HP-41CV and 1990 for the HP-41CX).
W.A.C. Mier-Jedrzejowicz, A Guide to HP Handheld Calculators and Computers , Tustin, California: Wilson/Burnett Publishing, 1997, pp. 65–66, 133.
David G. Hicks, The Museum of HP Calculators, http://www.hpmuseum.org/, accessed July, 2014.
Accession file.
Currently not on view
Object Name
electronic calculator
date made
ca 1982
Hewlett-Packard Company
Physical Description
plastic (case; keys; circuit board; template; display cover material)
metal (circuitry material)
ceramic (display circuit board material)
overall: 3.3 cm x 7.8 cm x 15.3 cm; 1 5/16 in x 3 1/16 in x 6 1/32 in
module: .5 cm x 3 cm x 3.8 cm; 3/16 in x 1 3/16 in x 1 1/2 in
place made
United States: Oregon, Corvallis
ID Number
accession number
catalog number
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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