Parity Bit

• Parity means equality.
• Parity bit is a bit added to a sending code to detect errors.
• Parity bit is of two types:
• Even Parity
• Odd Parity

Even Parity:

• Even Parity checks whether no of "1s" in code are even.
• Adding Parity bit:
• Adds "1"     -     "1" bits are odd.
• Adds "0"     -     "1"  bits are even.

Odd Parity:

• Odd Parity checks whether no of "1s" in code are odd.
• Adding Parity bit:
• Adds "0"     -     "1" bits are odd.
• Adds "1"     -     "1" bits are even.

Error Detection:

• A sends a file with code 1010110 of even parity.
• A Checks parity, no of '1s' are even, parity is "0".
• B receives a file with code 1000110
• B checks parity, no of  '1s' are odd, parity is "1".
• There is error in code sends a message to resend the code.

Hamming Code:

• Hamming Code is used to detect and correct errors.
• 7-Bit is used commonly in hamming code.
• Hamming code uses parity bits.
• In below figures the parity code is explained.