If you are using a video terminal, use the highest speed possible so that your screen updates as quickly as possible. If you must use a hardcopy terminal, don't push it beyond its mechanical limits. Today's high-speed printing terminal can run at 1200bps or higher. The codes are in the range of 0 to 127 decimal. The number of stop bits for transmission speeds of 300 bps or greater should be one.
Parity is a simple and nearly useless form of error checking.
The normal UNIX setting is even parity when the number of data bits is seven. When you use eight data bits, set parity to none. UNIX doesn't use the parity bit for anything, but you should set the terminal to match the host computer's hardware settings. If you are using a direct connection, you won't need a modem or other communication device. Once you've connected your terminal to the UNIX system, it's time to log in.