Here is the full set of commands listed in the manual. 
Ctrl-I A    Append line feeds onto carriage returns. 
Ctrl-I K    Don't append line feeds onto carriage returns. 
Ctrl-I B    Turn on bell (don't filter Ctrl-G). 
Ctrl-I C    Turn off bell (filter out Ctrl-G). 
Ctrl-I H    Enable 8th bit to be output to printer. 
Ctrl-I X    Disable 8th bit 
Ctrl-I nN   Set line length to "n" characters and disable video output. 
            This does not take the left margin into account. 
            Use Ctrl-I 0N to disable automatic line wrapping. 
Ctrl-I I    Output to screen and printer. 
Ctrl-I nL   Set left margin to "n". 
Ctrl-I nR   Set right margin to "n" (from left edge of page, not left 
            margin) - prevents word breaks in the region from the right 
            margin to the line width. 
Ctrl-I S    Do a screen dump of the 40-column text screen. 
Ctrl-I 2S   Do a screen dump of text pages 1 and 2 side by side. 
Ctrl-I nP   Set page length to "n".  Forces six line feeds after this 
            number of lines have been printed.  Use Ctrl-I 0P to disable 
            this feature. 
Ctrl-I Ctrl-Y  Change the command character to Ctrl-Y (other control 
               characters may be used instead).  This is necessary to allow 
               a Ctrl-I to be sent to the printer.  Use Ctrl-Y Ctrl-I to 
               set it back again. 
Defaults after printer firmware init are: left margin 0, right margin 
0, line length 0 (disabled), page length 0 (disabled), video on for 
BASIC or off for Pascal, line feed on for BASIC or off for Pascal. 
DIP Switch 1 controls 8th bit output: if ON (+), the 8th bit is not 
transmitted.  If OFF (-), the 8th bit is under program control. 
DIP Switches 2 to 4 control the printer type (for selecting the 
graphics command set). 
2   3   4 
ON  ON  ON     Epson Series, Star Gemini 
ON  ON  OFF    NEC 8023, C-Itoh 8510, DMP 85 
ON  OFF ON     Centronics 739-1 
ON  OFF OFF    Anadex 
OFF ON  ON     Okidata 82A, 83A, 92, 93, 84 
OFF OFF ON     Okidata 84 w/o Step II Graphics 
OFF ON  OFF    Apple Dot Matrix 
The graphics dump commands all start with "Ctrl-I G", followed by one 
of more of the following options.  The command is terminated by 
carriage return.  The default is to print Hi-res graphics page 1 
horizontally with inversion (white dot on screen = black dot on printer). 
2    Page 2 instead of page 1. 
S    Page 1 and 2 side by side (can't use rotated or double size). 
M    Graphics with 4-line text window (can't use rotated, double size or 
     left margin). 
D    Double size. 
E    Emphasized. 
I    Invert (black on screen = black on printer). 
L    Use left margin previously set by Ctrl-I nL. 
R    Rotate 90 degrees clockwise. 
Other notes from the manual: 
The Pascal 1.0 and 1.1 firmware entry points defaults to using Ctrl-Y 
as the command character, since Ctrl-I is used as a TAB for Pascal. 
Advanced commands: 
Ctrl-I U   Enable user output filter.  Each character will be passed 
           to a user subroutine at $300 (in A).  The fimrware is completely 
           bypassed.  The routine must JMP $CF03 when finished. 
Ctrl-I 1U  Similar to the above, but the routine is located at $D000 in 
           "bank A" of the language card, and must JMP $CF00 when finished. 
Direct hardware access: assuming Y=$n0, where n is the slot.  All 
locations return status for a read.  The write functions are: 
$C080,Y    Output byte to printer 
$C081,Y    Select bank 2 of ROM 
$C082,Y    Reset IRQ and IRQ flag 
$C084,Y    Output/interrupt on ACK 
The status register contains the following bits: 
7  IRQ flag 
6  Printer type (from DIP switches - order is not given) 
5  Printer type 
4  Printer type 
3  Busy 
2  Paper Empty 
1  Select 
0  Acknowledge 
RAM locations used by the firmware are (n = slot): 
$0478+n   Left Margin 
$04F8+n   Character Counter 
$0578+n   Line Length 
$05F8+n   Page Length 
$0678+n   Right Margin 
$06F8+n   Line Counter 
$0778+n   Current Command Character 
$07F8+n   Text Flags 
          7    Output high order bit 
          6    Video enabled 
          5    LF after CR 
          4    Bell On 
          3-0  Reserved 
Connector pinout for a Standard or Buffered Grappler+ is: 
Strobe    1 
D0        3 
D1        5 
D2        7 
D3        9 
D4       11 
D5       13 
D6       15 
D7       17 
Ack      19 
Busy     21 
Paper E. 23 
Select   25 
All others are ground. 
-- 
David Empson 
demp...@actrix.gen.nz 
Snail mail: P.O. Box 27-103, Wellington, New Zealand