A group of 8 bits is a byte. Typically one character is represented with one byte. The agreement by the American Standards Committee on what pattern represents what character is called ASCII. (There are several ways to pronounce "ASCII". Frequently it is pronounced "ásk-ee"). Most microcomputers and many mainframes follow this standard.

When a printer built to print ASCII receives the ASCII pattern for "A" (along with some control signals), it prints an "A". Printers built to other specifications (typically for mainframe computers) might print some completely different character if sent the same pattern.