RMTSHELL.BAT

echo off
if %1==0 goto LOCAL

:NotLocal
CTTY COM%1
REM Reassigns standard I/O to port with value in %1
Goto Shell

:Shell
%2 %3 %4 %5 %6 %7 %8 %9
CTTY CON
REM Restores standard I/O to the console (default/original)
Exit
echo on

:LOCAL
REM does not reassign standard I/O, uses CON
goto Shell