Page 370 - The ROV Manual - A User Guide for Remotely Operated Vehicles 2nd edition

362 CHAPTER 13 Communications
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FIGURE 13.35
ASCII character set.
of character sets called the American Standard Code for Information Interchange (or ASCII). The basic unit of serial data is termed the “byte” and is normally eight bits long (seven bits with a checksum for error control). This has evolved into the standard data byte of “8-N-1” for eight (8) data bits, no (N) parity bit, and one (1) stop bit. This abbreviation is typically given along with the line speed (e.g., “9600/8-N-1” for 9600 baud (baud5symbols per second)). The standard serial byte will be examined further below in the section on standard serial protocols.
13.3.2 Data representation
The ASCII character set was first issued for use with teletype machines in the early 1960s and has evolved as the worldwide standard of symbols for use in telecommunications. The character set dis- plays 27 possible characters that represent both the characters themselves as well as machine states for use in machine control (Figure 13.35). As an example of characters, 10000015“A” while 1000011 5 “a.” For a machine control example, 0000000 5 “NUL” while 1101100 5 “ESC.”
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