Character Codes Passport questions

1. What 3 different character systems exist and how many characters does each hold?
Ascii-128 characters, Extended Ascii-256 characters, Unicode-65,536 characters.

2. What are the decimal code equivalent of some letters in the alphabet? what are the Binary versions? a is 97 or 1100001. e is 101 1100101.

3. What are the differences with character codes of capital and lower case letter? They have a decimal difference of 32. The 32 bit is different. 0 is capital 1 is lower case.

4. What is meant by a parity bit? How does Parity work? what different parity systems are there? Parity bit is an extra bit on the end of the information to make sure it is correct and has not been changed. Parity works by either using odd or even parity. so if there is an odd or even number of 1 the end parity bit will be a 1 or 0. There are 1 bit and 3 bit parity. ! bit is most common because it requires less data to be sent and is therefore cheaper to implement.

5. What is meant by a check digit? How does this work? A check digit works by using the rest of the numbers then multiplying them and adding them. Then the check digit is the number between the total and the total rounded up to the nearest 10.

6. What is majority vote? How does it work? Majority vote is when the computer decides whether info is correct by what the majority of that bit is. so the info is sent 3 times and the majority of the 1s or 0s for that bit is what the computer assumes correct.