c

d

Shift

01000011

C

01000100

01000001

01100001

A

The basic ASCII code

D

The basic ASCII code uses 7 bits and so can represent 128 alphanumeric characters, punctuation marks and  control commands.The eighth bit is used as a parity bit to detect transmission errors. As this has limitations, over time the eighth bit was used to create so-called 'extended ASCII' variations. There are no standards for extended ASCII and  many different versions were used by different manufacturers. When a key is pressed a byte is transmitted to the processor which interprets it and transmits the corresponding character to the monitor or printer. Try it out on the keyboard. You can use the A, C and D keys and the Shift key to get capitals.

01100011

01100100

a

0 1 0 1 0 0 1 1

0 1 1 0 0 1 0 1

0 1 0 0 0 0 1 1

Well done! They are all correct.

Decoding

0 1 0 0 1 0 0 1

Decode the following bytes and enter the characters into the boxes below. Then press the Submit button to check your answers.

0 1 0 1 0 1 0 0

Sorry! Some of them are incorrect.

0 1 1 0 1 0 0 0

0 1 1 0 1 1 1 1

Submit

0 1 1 0 0 1 0 0

0 1 0 0 0 0 0 1