What is an ASCII table?
The American Standard Code for Information Interchange, abbreviated as ASCII, is a standard of character encoding system intended for electronic communication. ASCII table includes codes representing text in telecommunications equipment, like computers, mobiles, and other electronic devices.
Most modern character-encoding schemes are mainly based on the ASCII table, although they support various additional symbols and characters. IANA abbreviated from the Internet Assigned Numbers Authority prefers the name US-ASCII table for character encoding. Besides, the ASCII table is one of the IEEE milestones (shortened from the Institute of Electrical and Electronics Engineers).
History of ASCII table
ASCII was founded from the telegraph code. ASCII’s 1st commercial use was as a seven-bit teleprinter code that was promoted by Bell data services. On October 6, 1960, the ASCII standard table's work started. Simultaneously, the first meeting of the American Standards Association’s (ASA) X3.2 subcommittee began. ASA is now known as the American National Standards Institute or abbreviated as ANSI.
The first edition of the ASCII standard table was presented in 1963, and during 1967, the ASCII table underwent a significant revision and also experienced its most recent update version in 1986. When ASCII is compared to its earlier telegraph codes, the proposed Bell data services code and ASCII were ordered for far more convenient sorting, such as alphabetization and lists. They later added features and designs for devices other than teleprinters.
Use of ASCII table
In 1969, the use and work of the ASCII table for Network Interchange were first described. Later, in 2015, that document was formally elevated to an Internet Standard. The ASCII table is primarily based on the English alphabet and encodes around 128 specified characters right into seven-bit integers, as shown in the ASCII tables. Around 95 of the encoded characters and symbols are printable. Hence, all of these 95 printable characters include letters, numbers, control characters, and punctuation marks. It is built via digits from 0 to 9, l uppercase letters from A to Z, lowercase letters from a to z, and punctuation symbols.
Furthermore, the original ASCII table specification consisted of about 33 non-printing control characters and codes, which first came with Teletype machines. Most of these codes are obsolete, although a few of these codes are still commonly used, for instance, the carriage return, tab codes, and line feed characters. For example, the lowercase letter "i" in the ASCII table will be represented and encoded by binary like 1101001 = hexadecimal 69 (the message "i" is the 9th letter) = decimal 105.
How does ASCII work
To understand how an ASCII table works, you will need to know how a standard calculator functions. In that sense, be wary that the computational processes are typically based on a binary system in a computer, which means that ones and zeroes detect the functions. That is the main reason why the ASCII table is also built via this system.
The original ASCII standard signifies various characters among seven bits – meaning seven digits that notate either a zero or a one. The eighth bit, which is also called one full byte, is traditionally used for checking purposes. The extended versions are based on the ASCII standard use this exact bit to extend the accessible characters and codes to 256 (28). Each code corresponds to a seven-digit sequence of ones and zeroes, which may then be categorized as a decimal number or even as a hexadecimal number. The ASCII table characters are generally divided into several groups, such as:
- ASCII Control Characters (include from 0 to 31 and 127). Control characters are not ordinary printable characters. Control characters are meant to send commands right to the PC or directly to the printer. These characters are mainly based on telex technology, and with the use of these ASCII control characters, users can set line tabs and breaks. Nowadays, these control characters are almost out of service.
- ASCII Special Characters (include from 32 to 47 / from 58 to 64 / from 91 to 96, and from 123 to 126). Special characters consist of all printable characters and codes that are neither numbers nor letters. These characters include technical math and punctuation characters. The ASCII table also consists of non-visible but printable characters and does not belong or relate to the ASCII control characters category, as one may think.
- ASCII Numbers (include from 30 to 39). These ASCII numbers consist of only the ten Arabic numerals from 0 to 9.
- ASCII Letters (include from 65 to 90 and from 97 to 122). These letters can be divided into two main blocks, with the 1st group, including the uppercase letters and the 2nd group containing the lowercase letters.
Overview of ASCII table categories
Generally, values are represented in binary, hexadecimal, and decimal form on the ASCII code tables. The first two values of the ASCII table are typically used since they are the most common number systems for machines and humans. Concerning the hexadecimal system of values, it can be said that this system has the benefit of comprising around 16 characters (from 0 - 9 and A - F). Besides, they can signify large numbers along with fewer numbers than the other two categories. In that way, a byte may continuously be displayed via a maximum of two digits.
The ASCII table code order is often called "ASCII vertical order." The collation of data is usually done according to this order instead of using the "standard" alphabetical order (also called "collating sequence"). The significant deviations in the ASCII table order are the following:
– All uppercase letters come right before lowercase letters; for instance, the letter "Z" always precedes the letter "a."
– Numbers and many other punctuations mark always come before the ASCII letters.
– An intermediate order generally converts the uppercase letters directly into the lowercase letters before comparing them into the ASCII values.
Below you can see some of the examples taken from the main ASCII table. Note that there are not all the values included in:
ASCII control characters:
- 0000000 (Bin); 0 (Hex); 0 (Dec), NUL (ASCII Symbol); The zero character prompts the device not to do anything (Explanation); Control Character (Group).
- 0000101 (Bin); 5 (Hex); 5 (Dec); ENQ (ASCII Symbol); Represents a request that needs a response or an inquiry (Explanation); Control Character.
- 0001101 (Bin); D (Hex); 13 (Dec), CR (ASCII Symbol); It moves the cursor back right to the initial position of the line (so-called “Carriage Return”); Control Character.
- 0011100 (Bin), 1C (Hex), 28 (Dec), FS (ASCII Symbol); It marks the division of logical data blocks; Besides, it is hierarchically ordered, like file the largest unit, and file as the smallest unit. (so-called “Group Separator,” “File Separator,” “Record Separator,” and “Unit Separator”); Control Character.
- 0011110 (Bin), 1E (Hex), 30 (Dec), RS (ASCII Symbol); It marks the separation of logical data blocks that are hierarchically ordered; Control Character.
ASCII numbers:
- 0110000 (Bin), 30 (Hex), 48 (Dec), 0 (ASCII Symbol), Numbers (Category).
- E.g., 0110001 (Bin), 31 (Hex), 49 (Dec), 1 (ASCII Symbol), Numbers (Category).
Special ASCII characters:
- 0100011 (Bin), 23 (Hex), 35 (Dec), # (ASCCI Symbol), ,Pound sign (Explanation), Special Character (Group).
- E.g., 0100100 (Bin), 24 (Hex), 36 (Dec), $ (ASCII Symbol), Dollar sign (Explanation), Special Character (Group).
ASCII capital letters:
- 1000001 (Bin), 41 (Hex), 65 (Dec), A (ASCII Symbol), Capital letters (Group).
- E.g., 1000010 (Bin), 42 (Hex), 66 (Dec), B (ASCII Symbol), Capital letters (Group category).
- E.g., 1000011 (Bin), 43 (Hex), 67 (Dec), C (ASCII Symbol), Capital letters (Category).
ASCII special characters:
- 1011011 (Bin), 5B (Hex), 91 (Dec), [ (ASCII Symbol), Left square bracket (Explanation), Special character (Category).
- E.g., 1011100 (Bin), 5C (Hex), 92 (Dec), \ (ASCII Symbol), Inverse/backward slash (Explanation), Special character (Group category).
- E.g., 1011101 (Bin), 5D (Hex), 93 (Dec), ] (ASCII Symbol), Right square bracket (Explanation), Special character (Category).
ASCII lowercase letters:
- 1100111 (Bin), 67 (Hex), 103 (Dec), g (ASCII Symbol), Lowercase letters (Group).
- E.g., 1101000 (Bin), 68 (Hex), 104 (Dec), h (ASCII Symbol), Lowercase letters (Group).
Overall, the 8th bit, set to zero in case of an extended version using it, is allocated differently and varies across the various programs. In most cases, the extra space is mainly used to cater right for country-specific values and variations. However, the 1st 128 ASCII characters are preserved continuously in their initial form.
Which are ASCII printable characters
There are two types of ASCII table characters, namely printable character and non-printable characters. In this part, only the printable characters will be discussed. It is commonly approved that the Codes 20 hex to 7 Ehex is the ASCII printable characters representing digits, letters, punctuation marks, and some of the miscellaneous symbols. Overall, there are 95 ASCII printable characters in the table.
The ASCII Code 20 hex, the so-called "space" character, signifies the space among the space bar's works assembled. The space character is thought of and approved as an invisible graphic (instead of a control character). It is placed in the table below, but note that the below-listed table only includes some of these codes):
– 010 0001 (Bin), 041 (Oct), 33 (Dec), 21 (Hex), ! (ASCII symbol).
– 010 0010 (Bin), 042 (Oct), 34 (Dec), 22 (Hex), " (ASCII symbol).
The Code 7 Fhex corresponds to the non-printable control character representing "delete" (DEL). Earlier versions of the ASCII used the up arrow rather than the caret (5 Ehex) and the left arrow instead of using the underscore (5 Fhex).
The Code 7 Fhex corresponds to the non-printable control character representing "delete" (DEL). Earlier versions of the ASCII used the up arrow rather than the caret (5 Ehex) and the left arrow instead of using the underscore (5 Fhex).
Convert ASCII table characters
In the ASCII table, the system converts its binary digits (i.e., numbers) right into the non-printable and printable characters according to a particular standard, as listed in the main ASCII table (see above examples). Users may also perform these processes right without any aids. In that case, all users need to understand how to calculate in hexadecimal or binary characters. For instance, in a digit system, each number corresponds to the power on a specific basis, like in the decimal system, the base is generally – 10. Respectively, the respective bases are 2 and 16 for hexadecimal and binary systems. Users can multiply the value of the number by the value of the digit.
However, when using Windows, the users can still enter Unicode characters – thus, ASCII characters will be used as a key combination. To do this, the users must hold down the Alt key and then enter the decimal value of the particular character using the number pad on the PC or any other device’s keyboard.
What are the ASCII table benefits?
Nowadays, the ASCII table codes are still widely used, even though the UTF-8 has become far more critical when presenting a simple text. However, the Unicode has displaced only the old character encoding method previously used during the internet's introductory days since 2008. The benefit of using the UTF-8 is that the code is almost backwardly compatible, meaning that the ASCII is a subset of UTF-8, so the 1st ASCII 128 characters are identical. Since the ASCII may be considered the lowest common denominator of most news added encoding forms, the old encoding tip is still used in URLs and emails.
Moreover, the ASCII has long been quite commonly used for technical purposes as well as artistic ones. The ASCII art characters use exclusively printable ASCII table codes to produce some creative works. The spectrum varies from lettering to simple stick figures and real paintings. The ASCII table artists use unique codes' various brightness levels to create shade and light in their artworks.