sub send_message {
  my ($to, $from, $msg) = @_;

  # Turn on PPP link, and give it time to connect
  `ppp-on`;
  sleep 5;

  # Create and send message
  $msg = MIME::Lite->new(
    From => $from,
    To   => $to,
    Subject => 'ALERT',
  );
  $msg->attach(Type=>'TEXT', Data=>$msg);
  $msg->send;

  # Wait long enough for delivery
  sleep 5;

  # Turn off the link
  `ppp-off`;
}