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Alphanumericals or alphanumeric characters are a combination of
alphabetical Alphabetical order is a system whereby character strings are placed in order based on the position of the characters in the conventional ordering of an alphabet. It is one of the methods of collation. In mathematics, a lexicographical order is t ...
and numerical
character Character or Characters may refer to: Arts, entertainment, and media Literature * ''Character'' (novel), a 1936 Dutch novel by Ferdinand Bordewijk * ''Characters'' (Theophrastus), a classical Greek set of character sketches attributed to The ...
s. More specifically, they are the collection of
Latin letters The Latin script, also known as Roman script, is an alphabetic writing system based on the letters of the classical Latin alphabet, derived from a form of the Greek alphabet which was in use in the ancient Greek city of Cumae, in southern ...
and Arabic digits. An alphanumeric code is an
identifier An identifier is a name that identifies (that is, labels the identity of) either a unique object or a unique ''class'' of objects, where the "object" or class may be an idea, physical countable object (or class thereof), or physical noncountable ...
made of alphanumeric characters.
Merriam-Webster Merriam-Webster, Inc. is an American company that publishes reference books and is especially known for its dictionaries. It is the oldest dictionary publisher in the United States. In 1831, George and Charles Merriam founded the company as ...
suggests that the term "alphanumeric" may often additionally refer to other symbols, such as punctuation and mathematical symbols. In the POSIX/C locale, there are either 36 (A–Z and 0–9, case insensitive) or 62 (A–Z, a–z and 0–9,
case-sensitive In computers, case sensitivity defines whether uppercase and lowercase letters are treated as distinct (case-sensitive) or equivalent (case-insensitive). For instance, when users interested in learning about dogs search an e-book, "dog" and "Dog" a ...
) alphanumeric characters.


Subsets of alphanumeric used in human interfaces

When a string of mixed alphabets and numerals is presented for human interpretation, ambiguities arise. The most obvious is the similarity of the letters I, O and Q to the numbers 1 and 0. Therefore, depending on the
application Application may refer to: Mathematics and computing * Application software, computer software designed to help the user to perform specific tasks ** Application layer, an abstraction layer that specifies protocols and interface methods used in a c ...
, various
subset In mathematics, 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 ...
s of the alphanumeric were adopted to avoid misinterpretation by humans. In passenger aircraft,
aircraft seat map An aircraft seat map or seating chart is a diagram of the seat layout inside a passenger airliner. They are often published by airlines for informational purposes and are of use to passengers for selection of their seat at booking or check-in. ...
s and seats were designated by row number followed by column letter. For wide bodied jets, the seats can be 10 across, labeled ABC-DEFG-HJK. The letter I is skipped to avoid mistaking it as row number 1. In
Vehicle Identification Number A vehicle identification number (VIN) (also called a chassis number or frame number) is a unique code, including a serial number, used by the automotive industry to identify individual motor vehicles, towed vehicles, motorcycles, scooters ...
used by motor vehicle manufacturers, the letters I, O and Q are omitted for their similarity to 1 or 0. Tiny embossed letters are used to label pins on an V.35/M34 electrical connector. The letters I, O, Q, S, and Z were dropped to ease eye strain with 1, 0, 5, 3,and 2. That subset is named the DEC Alphabet after the company that first used it. For alphanumerics that are frequently handwritten, in addition to I and O, V is avoided because it looks like U in cursive, and Z for its similarity to 2.


See also

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Alphanumeric brand names An alphanumeric brand name is a brand name composed only of letters and numbers (alphanumericals). Examples include 7 Up, Saks Fifth Avenue, Audi A4, Canon A75. They may serve as abbreviations (e.g. 3M, formerly known as the Minnesota Mining and M ...
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Alphanumeric shellcode In hacking, a shellcode is a small piece of code used as the payload in the exploitation of a software vulnerability. It is called "shellcode" because it typically starts a command shell from which the attacker can control the compromised mac ...
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Alphanumeric keyboard The technology of computer keyboards includes many elements. Among the more important of these is the switch technology that they use. Computer alphanumeric keyboards typically have 80 to 110 durable switches, generally one for each key. The ch ...
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Binary-to-text encoding A binary-to-text encoding is encoding of data in plain text. More precisely, it is an encoding of binary data in a sequence of printable characters. These encodings are necessary for transmission of data when the channel does not allow binary ...
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Mathematical Alphanumeric Symbols Mathematical Alphanumeric Symbols is a Unicode block comprising styled forms of Latin and Greek letters and decimal digits that enable mathematicians to denote different notions with different letter styles. The letters in various fonts o ...


References

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