IBM 4400 manual Backspace, Graphics

Backspace

FUNCTION		ASCII CODE	PAGE
Graphics
	Graphics, Standard Density	ESC K n1 n2	171
	Graphics, Double Density	ESC L n1 n2	172
	Graphics, Double Density
	Double Speed	ESC Y n1 n2	173
	Graphics, Quadruple Density	ESC Z n1 n2	174
	Reassign Graphics Mode	ESC ? s m	184
†	Select Graphics Mode	ESC * m n1 n2	185
	Select 9-Pin Graphics Mode	ESC ^ m n1 n2 d1 ... dk	186
Other Functions
	Bell	BEL	160
† Cut-Sheet / Paper Feed Control		ESC EM n	164
†	Half-Speed Mode, On/Off	ESC s n	174
	Initialize Printer	ESC @	176
	Printer Deselect	DC3	183
	Printer Select	DC1	184
	Super-Set Commands	ESC } ;	192
	Unidirectional Printing, 1 Line	ESC <	194
	Unidirectional Printing, Set/Reset	ESC U n	194

Backspace

ASCII Code BS

Hex Code 08

Dec Code 8

Purpose Moves the logical print head to the left one character space toward the first character column.

Comment Assures that the previous printable characters are printed, then moves the logical print head one character space to the left at the current pitch setting (which includes double wide and ESC SP). If the logical print head bumps into the left margin, it stops.

†When backspacing over proportionally spaced characters, Epson printers move back the width of each proportional character; this emulation moves back based on the current cpi setting, as if proportional spacing is disabled.

†If one or more Backspace control codes follow directly after a Bit Image Graphics command (ESC K, ESC L, ESC Y, or ESC Z), the printer backspaces into the graphic pattern, the number of dots depending on the current cpi setting. For an Epson FX- 1050 printer, one Backspace sends the logical printhead directly to the beginning of the graphics pattern.

Example If you were to print five “T” characters, then two BS commands, then two “=” characters, the output would look like the sample below.

159