# in Serial.pm
our $port;

# in test_Serialpm.pl
print "Response num char; ".length($response)."\n";

Serial::port->close();

##</code><code>##

# in Serial.pm
use Exporter 'import';
our @EXPORT_OK = (qw(Serial_Init $port));

# in test_Serialpm.pl
use Serial 'Serial_Init';

Serial_Init();