The following instructions are for PLUS 4.0 & 5.0.
This exploration was in response to a friend who took home the wrong copy
of Carbon Copy and found he could not contact his office computer.  He
lost a weekend he needed to work on a project.  The following changes to
CCHELP.EXE prevented his suffering from such an error again.

Only one instruction needs changing, a simple jump instruction.

Be sure to work with a copy of your program, not the original!!

On the recording of the session below, numbers like 0A75:8BA7 show memory
addresses.  On your session, the first four numbers may be different, but
the last four should be the same.  I began with DOS AND DEBUG.COM in drive
A and Carbon Copy in drive b.

RECORDING OF DEBUG SESSION:                 COMMENTS:

A>RENAME B:CCHELP.EXE CCHELP.X             |First Rename the file
A>DEBUG B:CCHELP.X                         |Call up the file under Debug
-SCS:0000 FFFE 75 1D 83 C3 02 83           |Search for the Instruction
0A75:8BA7                                  |It's at this address
-U0A75:8BA7                                |Type this to look at code
0A75:8BA7 751D          JNZ     8BC6       |This is the Instruction
0A75:8BA9 83C302        ADD     BX,+02     |  You want to change
0A75:8BAC 83C602        ADD     SI,+02     |
0A75:8BAF 81FB965E      CMP     BX,5E96    |
0A75:8BB3 75EE          JNZ     8BA3       |
0A75:8BB5 BE276E        MOV     SI,6E27    |
0A75:8BB8 B000          MOV     AL,00      |
0A75:8BBA E898FC        CALL    8855       |
0A75:8BBD E82AAF        CALL    3AEA       |
0A75:8BC0 E8B7FE        CALL    8A7A       |
0A75:8BC3 73FB          JNB     8BC0       |
0A75:8BC5 C3            RET                |
0A75:8BC6 E864A5        CALL    312D       |
-A0A75:8BA7                                |Type this then hit return
0A75:8BA7 JMP 8BC6                         |Type in JMP 8BC6 then hit
0A75:8BA9                                  | return twice
-W                                         |Write the program back to
                                           | disk
Writing 22EA6 bytes                        |
-Q                                         |Quit Debug
                                           |
A>RENAME B:CCHELP.X CCHELP.EXE             |Change name back to
                                           | CCHELP.EXE
                                           |

Note: Making these changes does not relieve you of your legal
responsibility to have two different copies for use on the remote and
local machines.
                             - Mary Sachs