The RPL character set is an 8-bit character set and encoding used by most
RPL calculator
An electronic calculator is typically a portable electronic device used to perform calculations, ranging from basic arithmetic to complex mathematics.
The first solid-state electronic calculator was created in the early 1960s. Pocket-si ...
s manufactured by
Hewlett-Packard
The Hewlett-Packard Company, commonly shortened to Hewlett-Packard ( ) or HP, was an American multinational information technology company. It was founded by Bill Hewlett and David Packard in 1939 in a one-car garage in Palo Alto, California ...
as well as by the HP 82240B
thermal printer
Thermal printing (or direct thermal printing) is a digital printing process which produces a printed image by passing paper with a thermochromic coating, commonly known as thermal paper, over a print head consisting of tiny electrically hea ...
.
It is sometimes referred to simply as "ECMA-94" in documentation,
although it is for the most part a
superset
In mathematics, a set ''A'' is a subset of a set ''B'' if all elements of ''A'' are also elements of ''B''; ''B'' is then a superset of ''A''. It is possible for ''A'' and ''B'' to be equal; if they are unequal, then ''A'' is a proper subset ...
of
ISO/IEC 8859-1
ISO/IEC 8859-1:1998, ''Information technology—8-bit single-byte coded graphic character sets—Part 1: Latin alphabet No. 1'', is part of the ISO/IEC 8859 series of ASCII-based standard character encodings, first edition published in 1987 ...
/
ECMA-94
ISO/IEC 8859 is a joint ISO and IEC series of standards for 8-bit character encodings. The series of standards consists of numbered parts, such as ISO/IEC 8859-1, ISO/IEC 8859-2, etc. There are 15 parts, excluding the abandoned ISO/IEC 8859-12. T ...
in terms of printable characters, and it differs from ISO/IEC 8859-1 by using displayable characters rather than control characters in the 0x80 to 0x9F range of
code point
A code point, codepoint or code position is a particular position in a Table (database), table, where the position has been assigned a meaning. The table may be one dimensional (a column), two dimensional (like cells in a spreadsheet), three dime ...
s.
Overview
In 1986,
the ''original'' series of RPL calculators (
HP-28 series
The HP-28C and HP-28S were two graphing calculators produced by Hewlett-Packard from 1986 to 1992.
The HP-28C was the first handheld calculator capable of solving equations symbolically.
They were replaced by the HP 48 series of calculato ...
) as well as the HP 82240A
thermal printer
Thermal printing (or direct thermal printing) is a digital printing process which produces a printed image by passing paper with a thermochromic coating, commonly known as thermal paper, over a print head consisting of tiny electrically hea ...
used a
modified variant of the
HP Roman-8 character set, of which characters above 147 could not be displayed on the calculator, only be printed.
This changed with the introduction of the HP 82240B printer in 1989
and the
HP 48 series in 1990, which came with a new character set now based on ECMA 94 / ISO 8859-1 instead of HP Roman-8, but with the control codes in the range 128 to 159 (0x80 to 0x9F) being replaced by additional displayable characters. Compared to ISO 8859-1, code point 127 (0x7F) showed a medium shaded gray box like in the former HP Roman-8 based character set. Code points 131 (0x83) to 142 (0x8E) were also taken over from the former HP Roman-8 based character set. In addition to this, code point 31 (0x1F) was used for ellipsis (
…
The ellipsis (, plural ellipses; from , , ), rendered , alternatively described as suspension points/dots, points/periods of ellipsis, or ellipsis points, or colloquialism, colloquially, dot-dot-dot,. According to Toner it is difficult to es ...
)
and code points 169 (0xA9) and 174 (0xAE) showed ambiguous glyphs which could be viewed as inverse circled number
❸
3 (three) is a number, numeral (linguistics), numeral and numerical digit, digit. It is the natural number following 2 and preceding 4, and is the smallest odd prime number and the only prime preceding a square number. It has religious and cul ...
or
copyright symbol
The copyright symbol, or copyright sign, (a circled capital letter C for copyright), is the symbol used in copyright notices for works other than sound recordings. 17 U.S.C. The use of the symbol is described by the Universal Copyright Conv ...
(
©) and as
❷
2 (two) is a number, numeral and digit. It is the natural number following 1 and preceding 3. It is the smallest and the only even prime number.
Because it forms the basis of a duality, it has religious and spiritual significance in many ...
or
registered trademark
A trademark (also written trade mark or trade-mark) is a form of intellectual property that consists of a word, phrase, symbol, design, or a combination that identifies a product or service from a particular source and distinguishes it from ot ...
symbol (
®), respectively.
This ''first version'' of the character set also had a
non-breaking space
In word processing and digital typesetting, a non-breaking space (), also called NBSP, required space, hard space, or fixed space ...
at position 160 (0xA0).
Translation from HP-48 to HP-28 character set:
In a ''revision'' of this character set in 1999, code point 160 (0xA0) was redefined to hold the
euro sign
The euro sign () is the currency sign used for the euro, the official currency of the eurozone. The design was presented to the public by the European Commission on 12 December 1996. It consists of a stylized letter E (or epsilon), crossed by ...
(€) in the
HP 49/50 series
The HP 49/50 series are Hewlett-Packard (HP) manufactured graphing calculators. They are the successors of the HP 48 series.
There are five calculators in the 49/50 series of HP graphing calculators. These calculators have both algebraic ...
(including the
HP 48gII),
now deviating from ISO 8859-1. Code points 169 (0xA9) and 174 (0xAE) were now clearly defined as holding the
copyright
A copyright is a type of intellectual property that gives its owner the exclusive legal right to copy, distribute, adapt, display, and perform a creative work, usually for a limited time. The creative work may be in a literary, artistic, ...
(
©) and
registered trademark
A trademark (also written trade mark or trade-mark) is a form of intellectual property that consists of a word, phrase, symbol, design, or a combination that identifies a product or service from a particular source and distinguishes it from ot ...
(
®) symbols in compliance with ISO 8859-1, whereas the corresponding glyphs still resembled the inverse circled numbers more.
The last calculator supporting this variant of the character set was the
HP 50g
The HP 49/50 series are Hewlett-Packard (HP) manufactured graphing calculators. They are the successors of the HP 48 series.
There are five calculators in the 49/50 series of HP graphing calculators. These calculators have both algebrai ...
introduced in 2006 and discontinued in 2015.
In a parallel development, the
HP 38G
The HP 38G (F1200A, F1892A) is a programmable graphing calculator by Hewlett-Packard (HP). It was introduced in 1995 with a suggested retail price of . HP credits a committee of eight high school, community college, and university teachers ...
also used the HP 48 series' character set internally. Starting with the
HP 39G in 2000, the superscript 3 (
³) at code point 179 (0xB3) was replaced by a superscript -1 (
−1) in the
HP 39/40 series (except for the
HP 39gII
HP 39/40 series are graphing calculators from Hewlett-Packard, the successors of HP 38G. The series consists of six calculators, which all have algebraic entry modes, and can perform numeric analysis together with varying degrees of symbolic ...
, which started to use
Unicode
Unicode or ''The Unicode Standard'' or TUS is a character encoding standard maintained by the Unicode Consortium designed to support the use of text in all of the world's writing systems that can be digitized. Version 16.0 defines 154,998 Char ...
).
Code point 160 (0xA0) was also changed to the
euro sign
The euro sign () is the currency sign used for the euro, the official currency of the eurozone. The design was presented to the public by the European Commission on 12 December 1996. It consists of a stylized letter E (or epsilon), crossed by ...
(€)
in this ''third variant'' of the character set. The last calculator supporting this variant of the character set was the
HP 40gs
HP 39/40 series are graphing calculators from Hewlett-Packard, the successors of HP 38G. The series consists of six calculators, which all have algebraic entry modes, and can perform numeric analysis together with varying degrees of symbolic ...
introduced in 2006 and discontinued around 2011.
Hewlett-Packard never defined an official Unicode translation, hence several variants evolved in the community, differing in code points 31 (0x1F), 127 (0x7F), 128 (0x80), 129 (0x81), 133 (0x85), 134 (0x86), 158 (0x9E), 160 (0xA0), 169 (0xA9), 174 (0xAE), 178 (0xB3), 181 (0xB5) and 223 (0xDF).
The fact that the Unicode equivalent for x-bar at code point 129 (0x81) is a combination of two characters (x̅) could cause problems in translations, therefore it was suggested to use U+0101 (ā) instead.
Characters which cannot be reasonably transcoded should be mapped to code point 127 (0x7F), similar to what the calculators do when communicating with older printers like the HP 82240A.
Since the calculators allow fonts to be redefined (using
FONT→,
→FONT,
MINIFONT→,
→MINIFONT) other codepages can be emulated for as long as symbols which are available on the keyboard or are otherwise associated with specific functionality by the calculator aren't replaced by unrelated symbols.
Code page layout
The following table shows the HP RPL character set. Each character is shown with a potential
Unicode
Unicode or ''The Unicode Standard'' or TUS is a character encoding standard maintained by the Unicode Consortium designed to support the use of text in all of the world's writing systems that can be digitized. Version 16.0 defines 154,998 Char ...
equivalent in the tooltip. Where special
HP TIO codes are defined to enter the character, they are given as well.
The other characters can be entered using the
\nnn TIO code syntax with nnn being a three-digit
decimal number
The decimal numeral system (also called the base-ten positional numeral system and denary or decanary) is the standard system for denoting integer and non-integer numbers. It is the extension to non-integer numbers (''decimal fractions'') of the ...
.
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See also
*
HP trigraphs
*
Western Latin character sets (computing)
Several 8-bit character encoding, character sets (encodings) were designed for binary representation of common Western European languages (Italian language, Italian, Spanish language, Spanish, Portuguese language, Portuguese, French language, Fren ...
*
Hewlett-Packard calculator character sets
Notes
References
Further reading
*
{{character encoding
Calculator character sets