A Byte is 8 bits.
In telecommunications standard it is usually more properly referred to as
- 0 or 1
- true or false
- yes or no
So by combining 8 of these bits you can represent say
- a number from 0 to 255
- a single character in a sentence
- a sample of a sound waveform
Since a string of 8 bits is a bit cumbersome to write, it is more convenient
to represent a byte by 2 hexadecimal numbers.
So 01111110 can be represented by 7E.