The HP-41C series are programmable, expandable, continuous memory handheld RPN calculators made by Hewlett-Packard from 1979 to 1990. The original model, HP-41C, was the first of its kind to offer alphanumeric display capabilities. Later came the HP-41CV and HP-41CX, offering more memory and functionality.
HP-41CX with magnetic card reader and thermal printer
The HP-41C's alphanumeric display allowed it to display numbers, characters, and symbols.
The HP-41CV had a memory five times larger than that of the first model HP-41C. On the lower, inclined flank of the keys, the alphanumeric characters are printed in blue, which are accessible after pressing the "ALPHA" key top right.
The box (top) in which the HP-41CV was sold with most of the manuals, programming handbooks and accessories; the power supply is not depicted
Reverse Polish notation (RPN), also known as reverse Łukasiewicz notation, Polish postfix notation or simply postfix notation, is a mathematical notation in which operators follow their operands, in contrast to prefix or Polish notation (PN), in which operators precede their operands. The notation does not need any parentheses for as long as each operator has a fixed number of operands.
A promotional Hewlett-Packard "No Equals" hat from the 1980s – both a boast and a reference to RPN
