\F\ to |
\S\ to ^
\T\ to &
\R\ to ~
\E\ to \

##</code><code>##

  $msgu =~ s/\\F\\/\|/g;
  $msgu =~ s/\\S\\/\^/g;
  $msgu =~ s/\\T\\/\&/g;
  $msgu =~ s/\\R\\/\~/g;
  $msgu =~ s/\\E\\/\\/g;

##</code><code>##

"AB\T\F\S\CD"

##</code><code>##

"AB&F^CD"

##</code><code>##

"AB\T|S\CD"