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";    

}