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<CTRL>-1
n>
allows you to give a string of characters which will be
interpreted as a series of hexadecimal codes to be sent to the printer. In
this case,
n
is the number of characters to be sent. The character string
which then follows the command will consist of 2n characters - a pair
to represent each hexadecimal number.
For example, the printer escape code sequence <ESC> 3
m
sets the
line spacing in steps of
m/216
of an inch. To set the line spacing to
160/216 inch, the ASCII code 160 (decimal) or AO (hexadecimal) is the
code used
form.
The full sequence you would use in this case is:
<CTRL>-1 3> 18 33 AO
or in BASIC:
CHR$(9); "3> 18 33 AO"
The pairs of characters can be separated by a space to make them
easier to read, but a large number of spaces will reduce the speed at
which the program will run. Note that even if the first character of a
pair is a zero, both digits must be given.
This command is particularly useful for sending bit image data
from word processors.
<CTRL>-1 nT allows the next
n
characters to be sent to the printer
without any interpretion by the interface. For example the command
<CTRL>-1 75T would send the next 75 characters to the printer
irrespective of whether they are control characters used by the
interface card or DOS. This mode of operation is termed 'transparent
mode'.
If
n
is given as 0, using the command <CTRL>-1 OT, transparent
mode is set for an infinite number of characters. This means that if you
do wish to use the <CTRL>-1 commands again, you first have to switch
the card off and on again. It also means that a line feed is not added to
a carriage return by the interface, and your software must give line
feed commands where they are needed.
This command is useful for sending a string of characters for bit
imaging or downloading user-defined characters, since no extra
characters are added by the interface and also none are lost by being
interpreted. An example is shown in the section on bit imaging.
The <CTRL>·I H and <CTRL>-1 X commands can be used to control
the high bit of all data passed to the printer. This can be useful for
32
\
J
j)
'
getting round the problem of the way the APPLE handles the high bit
of data sent to the printer. Normally, it is set to zero by the APPLE
system software. The <CTRL>-1 H command allows you to force the
high bit to be set to 1. This is the only way of sending characters with
codes greater than 127 using the
CHR$
function. Otherwise transparent
mode has to be used.
33
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