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Printing Bar Codes
Page B-5
Entering/Exiting Bar Code Mode
Bar code mode is entered by sending the escape sequence: ESC ESC ETX (27 27 03
decimal, 1B 1B 03 hex).
Bar code mode is used only to process the bar code sequences described in this
document. While in bar code mode, other printable text, text mode escape sequences
and control characters, graphics data, and graphics mode escape sequences and
control characters should not be sent to the printer.
To exit bar code mode, use the sequence ESC ESC ? (27 27 63 decimal, 1B 1B 3F
hex) to return to the previously selected emulation mode, or you may use a different
ESC ESC n sequence to select a different emulation mode.
The Bar Code Control Character
Except for a few ASCII control characters supported by bar code mode, all bar code
sequences are introduced by the “bar code control character”. The “bar code control
character” is the printable ASCII caret character “^” (94 decimal, 5E hex).
Note in particular that the ESC control code (27 decimal, 1B hex) is not used in bar
code mode. When the caret character “^” is seen in this chapter, it does not mean
ESC and it does not mean “control-_” !
Other Control Characters
BEL is processed and causes the printer to ring the bell. This is supported so that you
may annoy the printer operator without exiting bar code mode.
ETX is processed so that ETX/ACK software handshake will work in bar code mode.
(As an aside, XON/XOFF software handshake will also work in bar code mode.
However, XON/XOFF characters are transmitted only from the printer to the host;
XON/XOFF characters should not be sent to the printer.)
FF is supported so that you may easily reach top of form without exiting bar code
mode.
LF advances the paper to the next line feed boundary at the currently selected line
pitch. If already positioned at a line feed boundary, this will peform a full line feed, if
not a partial line feed will be performed to position the paper at the next line. This
allows the paper to be positioned properly for text printing after bar code mode is
exited.
All other control characters are ignored in bar code mode.