Parity is a form of “error checking” where the computer checks to see if all the data it was supposed to get really did come through. You will most likely be confronted with parity when you use a telecommunications package to communicate through your modem. In fact, that’s probably why you’re reading this. The dialog box where you can set the serial port settings always wants to know the parity. The default setting is probably the safest thing to use if you don’t know a reason to change it.
But here are a few tips, according to Scott Watson’s White Knight manual: If two personal computers are talking to each other, both sides should use no parity and 8 bits (data bits). If your personal computer is connecting to a bbs (bulletin board service), use no parity and 8 bits. If you are using 8 bits, you’ll always use no parity or ignore parity. Use “ignore parity” if you are sending international characters like n or C. Otherwise use no parity. If you are using 7 bits (databits), you need to use some form of parity.
A similar parity scheme is used in most pcs and many other types of computers to continuously check memory chips for errors. You can get parity errors right in the middle of your work, especially during smalltown power problems. Some Macs purchased for the government have parity checking as an option; IBM is a firm believer in parity checking.
For data transmission over a serial connection, parity checking is less reliable than XMODEM, Kermit, and other checksum-based protocols.