(7)NUL (Null)

The NUL code is regarded as the termination for tabulation setting sequence. The lack of the NUL code would cause incorrect data printout.

(8) ESC K

Input of this code in the Text Mode causes the Printer’s operation mode to be converted from Text to Normal-density Bit Image. Refer to paragraph 4.1, section 4, for details.

(9) ESC L

Input of this code in the Text Mode causes the Printer to perform dual-density bit image printing. Refer to paragraph 4.2, section 4, for details.

4. Control Codes in the Bit Image Mode

Most of the abovementioned control codes are normally used in the text mode. Control codes associated with the Bit Image mode will be discussed next.

Each computer has its unique way of handling graphics.

For example, in the CBM computer there is a set of 64 special graphic characters

that can be used to draw and plot with. On the other hand, the APPLE II computer has no graphic characters but a rich variety of graphic statements that allow you to control any dot in a 280-by-193 screen matrix. As well as the latter “APPLE II,”

the

MX-80

Type

II has no character generated graphics but allow you to control

all

the

8 needles

freely and programmably by means of the so-called

“Bit

Image”.

To

do

that

you

have to switch the printer from the text mode to

the

bit image

mode by inputting an escape code. This bit image mode expands the ability of the

printer.

 

 

 

 

 

The printer enters bit image

mode when

ESC K

or

ESC L

code is input, and utilizes

a raster scan technique that

enables the

printing

of

vertical

columns of 8 dots across

a page during each pass of the print head. To receive bit image data, RAM (128 bytes) of an IC on the control circuit board is used exclusively. When the bit image data received by the printer exceeds the RAM capacity, the printer will start

printing

bit image data

from the first-in data,

so that the RAM may always be filled

up with

data up to its

capacity of 128 bytes.

 

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