Keywords: MACTERMINAL BACKSPACE DEL BS VAX VMS EDT
 
    Instructions to patch MacTerminal so that it sends an ASCII DEL instead of
    an ASCII BS when Backspace is typed.  Useful for those who talk to VAX/VMS
    with MacTerminal
 
 
Instructions to change MacTerminal to transmit an ASCII DEL when
Backspace is depressed
 
The VMS operating system (as well as other DEC and probably some other
manufacturers) makes heavy use of the ASCII DEL (or RUBOUT) (hex 7F)
code for correcting errors.  When using MacTerminal, there is no
single-key way to generate the DEL code.  Command-Backspace does
generate this code, but this is awkward.  Worse, it is non-standard with
respect to other Mac usage.  If you use several editors, some on the VAX
and others on the Mac, it is not automatic to figure out what you have to
do to wipe out the last character you typed.   Fortunately, MacTerminal
can convert each keystroke before it transmits it.  Thus it is possible to
change MacTerminal to generate the DEL when Backspace alone is typed.
It is obviously also possible to remap anything; this is left as an
exercise for the reader.
 
The conversion tables are stored near the beginning of MacTerminal's
resource fork.  There are two tables, one for the VT100 mode and one for
the TTY mode (this is actually gueswork). The tables have  one entry for
each key, with sixteen values per entry (apparently covering all
combinations of Caps Lock, Shift, Option, and Command).  The first value
in each pair is the un-command one; the second is the command one.
What has to be done is to change Uncommand-Backspace to generate an
ASCII DEL (7F in hex), and Command-Backspace to generate an ASCII BS
(08 in hex).  In all eight words have to be changed to handle the
Shift/Option/ Caps Lock cases.  At this point, I have already told you
more than I know.
 
Detailed Instructions:
 
1. Use the Finder to copy MacTerminal to a different disk
2. Launch FEdit
3. Choose "Display in Hex" from  "Options" Menu
4. Horizontal Scroll to Blk : 0007
5. Choose "Hex Modify" from "Edit" Menu
6. Click at 00A6 (the "0" in the first of eight "087F"s)
7. Type "7F087F087F08...." until all eight "087F"s become "7F08"
8. Choose "Write Block" from "Edit" Menu (this changes VT100 mode)
9. Click "OK" in dialog box
10. Horizontal Scroll to Blk : 000B
11. Choose "Hex Modify" from "Edit" Menu
12. Click at 0136 (the 0 in the first of eight "087F"s)
12. Type "7F087F087F08..." until all eight "087F"s become "7F08"
14. Choose "Write Block" from "Edit" Menu (this changes TTY mode)
15. Click "OK" in dialog box
16. Choose "Quit" from "Edit" Menu
17. Rename the file MacTerminal (VAX)
18. Choose "Get Info" from the "File" meno
19. Type a comment in the Description field indicating that you have
      changed the Backspace key to generate ASCII DEL