use warnings;
use strict;

use IO::Termios ();

$| = 1;

my $fh = IO::Termios->open('/dev/ttyAPP4', '115200,8,n,1')
    or die "IO::Termios->open: $!";

`stty cbreak`;
print $fh "Begin\n\r";

while(1){
    my $inchar=<$fh>;
#    my $outchar=<>;
    if($inchar){
        print $inchar;
        print $fh ".";
    }
#    if($outchar){
#       print $fh $outchar;
#    }
}