IBM 1800409-001A - Manual (Page 399)

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 ASCII Control
Keyboard Name Hex Function
^A SOH 0x01 Quote data character
^C ETX 0x03 Abort job and flush to end of file
^D EOT 0x04 End-of-file marker
^E ENQ 0x05 (Reserved for future use)
^Q DC1 0x11 XON in XON/XOFF flow control
^S DC3 0x13 XOFF in XON/XOFF flow control
^T DC4 0x14 Job status request
^\ FS 0x1C (Reserved for future use)
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
character is the character itself XORed with the ASCII value 0x40.
For example, to send the value 0x14(^T) as data, send the
two-character sequence 0x01 0x54 (^a T) instead. (ASCII “T” is
the result of XORing ^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 Supplement for
Version 2011, Adobe Systems, Inc., January 24, 1992).
Appendix D
A d d i t i o n a l T e c h n i c a l I n f o r m a t i o n D - 1 1