open( com, "+<","/dev/ttyUSB0" ) || die "Cannot open serial port : $!\n"; my $raw = "\x2F\x3F\x21\x0D\x0A"; print com $raw; my $raw = "\x06\x30\x30\x30\x0D\x0A"; print com $raw; while( 1 ) { my $in =