What is a Parity Bit?
A parity bit is used for error checking against an array of data. One byte is made up of eight bits of data, seven that actually contain data and the parity bit. The bit helps ensure that the array is always either odd or even, one or zero. The parity bit allows transmitted data to be checked for errors by allowing the receiving computer to make sure a group of bits is either odd or even when the data arrives. When data is transmitted, the binary digits sent must match the length of bits that the recipient is expecting. If the data expected is even and the data sent with its parity bit is odd, the recipient can reject the data because of an error in parity. A parity bit helps ensure that each array of data has an even number of ones, for even parity or an odd number of ones for odd parity. Adding the extra bit to the data packet will allow the data to quickly be checked for errors when received. The parity bit acts as an error detecting code or mechanism so unexpected data is not recei
– Explain the difference between an odd parity bit and an even parity bit. – Given a character, calculate an odd or an even parity bit of characters using ASCII or EBCDIC encoding. – What kind of transmission errors that parity bits can detect? – What kind of transmission errors that parity bits cannot detect? – If a malfunctioning of hardware changes all transmitted bits including a parity bit to 0, can a parity bit catch this error? Explain. – If a malfunctioning of hardware changes all transmitted bits including a parity bit to 1, can a parity bit catch this error? Explain. – What is checksum? – What is a general process to calculate checksums? – What are the advantages and disadvantages of checksums? – What is cyclic redundancy check (CRC)? – What are the mechanisms used to calculate CRC and how do they work? – What are vertical errors? Give some examples of vertical errors. – What are burst errors? Give some examples of burst errors. Chapter 8: LAN Technologies and Network Topolog
Use of the wrong parity setting in a communications program may produce screens full of garbage characters. If this happens, check to see what parity settings the computer to which you are connecting expects. If you do not have this information, try connecting with a different parity setting and see if this produces legible text.
