Device Control 1 (Dc1) / Select Or Xon; Device Control 2 (Dc2) / Cancel Condensed Print; Device Control 3 (Dc3) / Deselect Or Xoff; Device Control 4 (Dc4) / Cancel Double-Wide Print - IBM 4247 A00 User Manual

Device Control 1 (DC1) / Select or XON

This control has different meanings depending upon the currently active interface.
v Parallel interface (Select): DC1 selects the printer.
v Serial interface (XON): DC1 is treated as a NUL if received from the host. The

Device Control 2 (DC2) / Cancel Condensed Print

This control cancels or ends condensed (17.1 or 20 CPI) printing. DC2 is a buffer
terminating control; if printable data at a different characters-per-inch setting is
buffered, that data is printed before the setting is changed. The current presentation
position becomes the next printable column at the new character-per-inch setting.
CPI can be changed within a print line.

Device Control 3 (DC3) / Deselect or XOFF

This control has different meanings depending upon the currently active interface.
v Parallel interface (Deselect): DC3 is treated as a NUL.
v Serial interface (XOFF): DC3 is treated as a NUL if received from the host. The

Device Control 4 (DC4) / Cancel Double-Wide Print

This control cancels double-wide printing if double wide was selected with the Shift
Out control. The characters-per-inch setting returns to the previous value.

Cancel (CAN)

This control purges all buffered data. All data received after the most recent buffer
terminating control is discarded. For a list of buffer terminating controls, see "Buffer
Terminating Conditions" on page 241. Any data received after Cancel is processed
normally. Cancel does not change the current presentation position.

Space (SP)

This control moves the print position one character space to the right.
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4247 Printer Model A00 User's Guide
11
printer sends DC1 (XON) to the host to control data pacing if XON/XOFF pacing
is selected.
12
13
printer sends DC3 (XOFF) to the host to control data pacing if XON/XOFF pacing
is selected.
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18
20