APPENDIX F

The prior code sequence also diverts all output to the printer ONLY! The video display is disabled after the CTRL-I # N sequence. The way to bring it back is by:

<CTRL I> I

In the process, the printer width defaults back to 40 columns.

Apple Mush

But how do we send control characters to the printer? The most obvious way is with the CTRL key on the keyboard. Let’s try it.

FIRST: activate the printer by typing PR#l <return>.

SECOND: hold down the CTRL key and press I.

THIRD: type 80N<return>.

Wonderful! Not only does nothing print on the screen, but the printer says

?SYNTAX ERROR.

Not to worry. Try pressing a few keys on the keyboard followed by <return>. The video is disconnected, but the printer works fine. If there is a program in memory, it will LIST fine up to 80 columns wide. To regain control of the video, use the CTRL key again:

<CTRL I>

I <RETURN>

A cleaner way to do the same thing is with the BASIC language CHR$(9). Try:

PRINT CHR$(9) “80N”

This kicks us into the printer-only mode without an annoying ?SYNTAX ERROR. To return, use:

PRINT CHR$(9) “I”

Type carefully as the latter doesn’t show up on the screen.

Special Apple Graphics Trick for Long Lines

When printing long lines of graphics, the Apple can be quite finicky. To smooth out the problem, add this line at the beginning of a graphics program, after the PR#l:

9 PRINT CHR$(9); “255H”

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