sub atsend {

    my ( $me, $msg ) = @_;
    my $cnt = 0;
    print "\nThe port \$me in keypress function is $me\n";

    # Write message on port
    $me->port->purge_all;
    $cnt = $me->port->write($msg);

    my $lbuf=length($msg);
    my $ret;

    while ($cnt < $lbuf)
    {
       $ret = $me->port->write(substr($msg, $cnt));
       $me->write_drain();
       last unless defined $ret;
       $cnt += $ret;
    }

    $me->log->write('debug', 'atsend: wrote '.$cnt.'/'.length($msg).' chars');

    # If wrote all chars of `msg', we are successful
    return $cnt == length $msg;
}



##</code><code>##

sub keypress
{

 my ($port_no,$key) = @_;
 $port_no =~ m/(\d+)/g;
print "\nThe port \$port_no in keypress function is $port_no\n";
 my $ms=$1;

 use Device::Modem::GSM;
 my $mod= new Device::Modem::GSM(port => "/dev/$port_no",
                                  log=> 'file,logfile.log',
                                  loglevel => 'info' # default is 'warning'
                                  );
 $modem[$ms]=$mod;

 $key =~ s/^\s+//;# to remove leading whitespace
 $key =~ s/\s+$//;# to remove trailing whitespace
 my  $st = "AT+CKPD="."\"$key\"".",1,1" ;


 $modem[$ms]-> atsend($st . Device::Modem::CR);
 
my ($ok, $response) = $modem[$ms]->parse_answer($Device::Modem::STD_RESPONSE);

 return "$ok";    

}