9.a Does Parity catch all errors? Why not? Give some examples of ‘bad’ parity.

Parity does not catch all errors. If two (or four, or any even number) bits are mis-transmitted (or stored), the errors will not be detected. Consider the following situations:

Even Parity:

Message Stored	Parity bit added	Message Transmitted
0010011	0010011 1	01010011
1001110	1001110 0	10001110

Odd Parity:

Message Stored	Parity bit added	Message Transmitted
0010011	0010011 0	01010010
1001110	1001110 1	10001111