IBM 4400 Edit Mode, NUL Code

Edit Mode
63
Edit Mode
Any printable character in the data stream can replace printable characters or
spaces already loaded in the print buffer. The space character (hex 20) is
used to skip characters in the print buffer that are not to be replaced and,
similar to underlining or deleting, the new characters are inserted in the
appropriate positions. Table 13 illustrates the edit mode. Note th at the editing
function replaces characters; it cannot be used to print the same character
twice(do uble strike) in the same location. Use the DEL code (hex 7F) to make
a character blank.
NOTE: Inorder for edit mode to work correctly, the protocol must be
configured for a carriage return only. If configured for a carriage
return and a line feed, the contents of the buffer are printed upon
receipt of the CR code, disabling the editing function.
NUL Code
NUL (hex 00) is ignored by the printer and can be used as a fill character;
however, it can not be used to add blank spaces since it is not a spa ce
character.
Table13. CR Ed it Mode Example
EnterinPrintBuffer PrintedResult
Example 1
AAABBBCCC (CR)
SSSSDSSSB (LF)
AAABDBCCB
Example 2
ABCDEF (CR)
______ (CR)
ABCDEF
Key: S=Space (hex 20);
LF =Line Feed (hex 0A);
CR =CarriageReturn (hex 0D)