Epson SQ-2000, Operating Manual

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Apple Computers
The Apple II computers present two problems when using
them with a printer like the SQ-2000. First, they can only send
seven bits of data to the printer, and second, they use the code
ASCII 9 for internal initialization of the printer routines.
The seven-bit limitation presents the largest problem, but we
have two solutions to offer. The easiest, but more expensive,
solution is to purchase a printer interface card that addresses all
eight bits. Your Epson dealer will help you with this.
The other solution is to POKE codes directly to the printer
output port on the Apple II. You can use the following routine to
do this on an Apple II Plus computer:
100 IF PEEK(49601)>127 THEN 100
110 POKE 49296,N
where N is the code that you want to send to the printer. Line
100 checks the printer’s status and line 110 sends the code to the
printer.
The Apple II used ASCII 9 to initialize the computer’s printer
routines. This code and the following character or characters are
intercepted by the printer interface card and used to change the
modes (in somewhat the same way the printer uses escape
codes). You can divert all output to the printer instead of to the
screen by sending the following lines to the printer interface
card:
PR#1
PRINT CHR$(9) "80N"
Then type anything, followed by ENTER.
The CHR$(9) “BON” directs all subsequent output to the prin-
ter, up to 80 characters per line. You can cancel this by typing:
PRINT CHR$(9) "I"
or
PR#0
To avoid the problem with ASCII 9 you can change the printer
initialization code to something else; this frees the ASCII 9 to go
on to the printer. This routine will change the printer initializa-
tion code to ASCII 1:
PR#1 PRINT
CHR$(9); CHR$(1)
90