The use of binary codes to represent characters

Characters: The use of binary codes to represent characters

1.2.4b Data Storage: Characters

Data Storage: Characters — Note 2 of 4

What you need to know

Characters (letters, numbers, symbols) are represented in a computer using binary codes. Each character is assigned a unique binary value according to a character encoding standard such as ASCII or Unicode.

What to know

Each character is assigned a unique binary code — no two characters share the same code within a character set.
Characters are grouped logically and run in sequence — e.g. in ASCII, 'A'=65, 'B'=66, 'C'=67. Once you know one, you can work out others.
This sequential grouping also applies to lowercase letters (a=97, b=98) and digits (0=48, 1=49).

Key terms

Character Encoding: The process of converting characters into binary codes so they can be stored and processed by a computer.

Exam technique

Tip:If given that A=65, you can work out that D=68 (65+3). This is a common exam question.
Tip:UPPER-CASE and lower-case are DIFFERENT codes. 'T' and 't' have different ASCII values. If asked for 'T' (84), do NOT give 't'.

Example:'How is the word MOP represented in ASCII?' Each character's code is stored IN ORDER: 77 79 80, each converted to 8-bit binary and stored sequentially.

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