ASCII Values Alphabets ( A-Z, a-z & Special Character Table )

ASCII (American Standard Code for Information Interchange) is a standard character encoding used in telecommunication. The ASCII pronounced 'ask-ee', is strictly a seven-bit code based on the English alphabet. ASCII codes are used to represent alphanumeric data.

The code was first published as a standard in 1967. it was subsequently updated and published as ANSI X3.4-1968, then as ANSI X3.4-1977, and finally as ANSI X3.4-1986. Since it is a seven-bit code, it can at the most represent 128 characters. it currently defines 95 printable characters including 26 upper case letters (A to Z), 26 lower case letters, 10 numerals (0 to 9), and 33 special characters including mathematical symbols, punctuation marks, and space characters. They represent text in, telecommunications equipment, and devices. These include numbers, upper and lowercase English letters, functions, punctuation symbols, and some other symbols.

In total, there are 256 ASCII characters, and can be broadly divided into three categories:

1. ASCII control characters (0-31 and 127)
2. ASCII printable characters (32-126) (most commonly referred to)
3. Extended ASCII characters (128-255)

What is ASCII Value?

 ASCII stands for American Standard Code for Information Interchange, A character encoding standard that assigns unique numerical values to letters, digits, punctuation marks, and other symbols.

Why do we need ASCII Value representation?

In the physical world, you would use a pen and paper to write the message, and your friend would read the text directly. However, when it comes to digital communication, computers don't understand letters and symbols the way humans do. Instead, they process information in the form of binary code, which consists of 0s and 1s. This is where ASCII values come into play.

ASCII values serve as a bridge between human-readable text and computer-readable binary code. Each character, whether it's a letter, number, or symbol, is assigned a unique ASCII value ranging from 0 to 127. For example, the ASCII value of the uppercase letter 'A' is 65, while the lowercase letter 'a' has an ASCII value of 97. Similarly, the digit '0' has an ASCII value of 48.

How Computers Use ASCII to Understand Human Text?

Suppose you want to send a text message to your friend that reads, "Hello!" When you type this message on your phone or computer, each character is converted into its corresponding ASCII value. In this case, the ASCII values for "Hello!" are 72, 101, 108, 108, 111, and 33. These numerical values are then translated into binary code, which is transmitted to your friend's device. Upon receiving the message, their device converts the binary code back into ASCII values and finally displays the original text, "Hello!"

The Extended ASCII Codes (character code 128-255)

The table below adheres to the Windows-1252 (CP-1252) standard, an extension of ISO 8859-1, also known as ISO Latin-1. This standard differs from IANA's ISO-8859-1 by substituting control characters with displayable characters in the range of 128 to 159. Any characters that deviate from ISO-8859-1 are highlighted in light blue.

So what's before 33 and beyond 126?

1. ASCII values before 32 (0-31) are control characters. A character code is often used in in-band signaling as a reference point in a set of characters to avoid adding additional symbols to the text.
2. At 32, we have space, which is included as printed characters, however, it's not wrong to say space could also serve as a control character.
3. At 127, we have DEL (delete), which is a control character.
4. After 127, (128-255), we have Extended ASCII characters representing mathematical and other symbols that are not represented as keys and are not used in general.

Below are the ASCII values of Control Characters (0-31, 127):

Difference Between ASCII and Unicode

Conclusion

To summarize, the range of ASCII values for capital letters spans from 65 to 90, while for small letters, it extends from 97 to 122. Allocated in alphabetical sequence, the values for "A" and "Z" are 65 and 90, respectively, in uppercase. Similarly, the values for "a" and "z" in lowercase are 97 and 122, respectively.

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Article Tags :

• Computer Subject
• DSA
• ASCII