Device::Modem or Device::SerialPort will do the trick.

use Device::Modem;
my $modem = new Device::Modem( port => '/dev/ttyS1' );
die "Sorry, no connection with serial port!\n"
    unless $modem->connect( baudrate => 9600 );

$modem->atsend( 'ATD' );
print $modem->answer();
[download]