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fixed mode, the printer uses the quoting mechanism of the binary
communications protocol to distinguish between the special control
characters and print job binary data.
To differentiate data from the special control characters, any data that
is the same as one of the following special control characters must be
quoted:
ASCII
ASCII Name ASCII Hex
Keyboard
^A
SOH
^C
ETX
^D
EOT
^E
ENQ
^Q
DC1
^S
DC3
^T
DC4
^\
FS
A data byte is quoted by replacing it with a two-character sequence.
The first character is a ^A (ASCII hex 0x01), and the second charac-
ter is the character itself XORed with the ASCII value 0x40. For exam-
ple, to send the value 0x14(^T) as data, send the two-character
sequence 0x01 0x54 (^A T); ASCII "T" is the result of exclusive XOR-
ing ^T with 0x40.
This method of quoting guarantees that whenever the printer receives
any of the eight control characters, the control function is intended
regardless of whether the preceding character is a ^A. Any data byte
not equal to one of the eight special control characters is transmitted
by sending the data byte. For more information on BCP and quoting,
see the PostScript Language Reference Manual (Adobe Systems,
Inc., Reading, MA: Addison-Wesley, 1990, ISBN 0-201-18127-4), the
"Adobe Serial and Parallel Communications Protocols Specification"
(in Adobe Developer Support. Adobe Systems, Inc., February 14,
1992), and the "PostScript Language Reference Manual" (in Supple-
ment for Version 2011 , Adobe Systems, Inc., January 24, 1992).
Control Function
0x01
Quote data character
0x03
Abort job and flush to end of file
0x04
End-of-file marker
0x05
(Reserved for future use)
0x11
XON in XON/XOFF flow control
0x13
XOFF in XON/XOFF flow control
0x14
Job status request
0x1C
(Reserved for future use)
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