5525B/31/32 Line Matrix Printer LinePrinter Plus Programmer's Reference

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Chapter 4 Configuring the Epson FX-1050 Emulation with Control Codes
Graphics, Double Density
ASCII Code ESC L n1 n2
Hex Code 1B 4C n1 n2
Dec Code 27 76 n1 n2
Purpose Selects double density bit image graphics of 120 dots per inch
horizontally and 72 dots per inch vertically.
where (
n1 + 256 n2 ) defines the number of data bytes to follow.
DATA = ASCII characters for the dot pattern bytes.
n1 = (Number of DATA bytes) - 256( n2 )
(remainder of division of number of DATA bytes by 256,
sometimes referred to as MOD 256)
n2 = (Number of DATA bytes) / 256 (quotient of division)
NOTE: The DATA can be expressed in a CHR$(DATA) format with the
appropriate decimal values of the ASCII characters supplied,
especially in cases where the dot patterns of nonprintable characters
are required.
NOTE: “DATA” consist of 8-bit dot columns, with the MSB at the top, and “1”
bits producing dots. For more information, refer to Chapter 5.
Discussion Double density printing reduces print speed to half that of normal
density printing. You can change graphics density with the ESC
? command. This feature is widely used to move the print head
precisely, by printing blank dot columns.
Example The following example produces double density bit-image
graphics of the pattern used in the standard density bit-image
mode example. The amount of data must be doubled for double
density (the data are used 54 times rather than 27).