User's Manual Part 2

Chapter 5 — Control Code Definitions
58 6822 Series 80-Column Printer User’s Manual
Understanding Control Code Definitions
I/O Buffer
All characters and control codes received by the printer are stored in this
buffer. Characters and controls codes are read from this buffer and acted
upon to form the print buffer. Characters are removed from the I/O
buffer as they are processed.
Print Image Buffer
All characters go through this buffer on their way to the printed page.
This buffer contains the graphic image of the dots to print, from which
characters are rendered. It is cleared when its contents are printed.
Special Notations
The following information defines notations included in the format
definitions of the escape sequences, throughout this section.
Special Notations
Notation Description
(0) Used in the ASCII column of any of the Format definitions, indicates that its
value can only be zero (and not the character “0”). For example: Select Top-
Down Printing ESC US (0).
(1) Used in the ASCII column of any of the Format definitions, indicates that its
value can only be one (and not the character “1”). For example: Select
Bottom-Up Printing ESC US (1).
* When a number (at the end of an escape sequence) is marked with an
asterisk, then either the value corresponding to that number or the value of
the string character can be used for that number. For example, if 1* is
shown, then either the value (1), or the value of the string character
(decimal: 49, hex: 31) can be used.
NUL The NUL character is represented in the Dec column as 0, in the Hex
column as 00, and in the ASCII column as NUL.