use Strict;
	use IO::Socket;
    use IO::Select;

    my $COMport=33;
	
	#open Port or die if blocked / wrong port
	if (!open( PORT, "+>\\\\.\\COM$COMport" ))
		{  
			die ("Can't open COM$COMport");
		}
		
	PORT->autoflush(1);
	PORT->flush();

	print "\nEnter AT command:";
	my $ATcmd=<STDIN>;
	chomp($ATcmd); 		# remove CRLF
	$ATcmd =~ s/^\s+//;		# remove leading space
	$ATcmd =~ s/\s+$//;            # remove trailing space
	print "Sending: '$ATcmd'\n";
	print PORT $ATcmd . "\r\n";
	sleep(2);

		#Reading the response
		print "reading\n";
		while (1)
		{   
			my $ret=<PORT>;
			print $ret;
			if ($ret=~/^OK/ || $ret=~/^ERROR/) { last}
		}

	close(PORT);
    print "done!";