02 Section 7 - Characters

Question 1

What are alphanumeric character?

Answer 1

Alphanumeric characters are used to make words and strings, They include:

• upper and lower case letters
• digits 0-9
• symbols (e.g. ? + £)

Question 2

How do computers convert between alphanumeric characters and binary code?

Answer 2

They convert by using character sets
-when you press a button on your keyboard it sends a binary signal for what key you pressed and that signal is then translated by the character set

Question 3

What are character sets?

Answer 3

Character sets are collections of characters that a computer recognises from their binary representation

Question 4

What are the main types of character sets?

Answer 4

ASCII
Extended ASCII
Unicode

Question 5

What is ASCII?

Answer 5

ASCII is the most commonly used character set for English

• each ASCII character is given a 7 bit binary code
• this means that a total of 128 different characters can be represented
• an extra 0 is added to the start of the binary code so it fits as one byte

Question 6

What is Extended ASCII?

Answer 6

Extended ASCII is particularly useful for most European languages
-each character is given an 8-bit binary code, allowing for 256 characters to be represented

Question 7

What is Unicode?

Answer 7

Unicode covers all major languages

• it comes in several different forms and tries to cover every single character
• its most common forms are 16 and 32 bit binary codes