Thanks for the replies, but how is it useful that using a number as string? Because I'm not sure about the results yet. The thing is, I'm trying to learn a new protocol that I should use it to give orders to a machine remotely. Also I need to calculate a variable so I need numeric values instead of strings.

#!/usr/bin/perl
use warnings;
use strict;
use IO::Socket;

my ($SM,@ADRDSTN,@ADRSRC,$MID,$MDLH,$MDLL,$SUBMID,@CHreq,@Pity,@Flags,
+@Timeout,@Level,$NumOfSrcEl,@SrcEl,$NumOfDstnEl,@DstnEl,$Rsvd,@messag
+e,$CHECKSUM,$EM);

$SM = 0xfe;
@ADRDSTN= (0x00, 0x09, 0x01, 0x00);
@ADRSRC= (0x00, 0x08, 0x01, 0x00);
$MID= 0x01;
$MDLH= 0x00;
$MDLL= 0x18;
$SUBMID= 0x00;
@CHreq= (0x00, 0x61);
@Pity= (0xFF, 0x05);
@Flags= (0x00, 0x20);
@Timeout= (0x00, 0x00);
@Level= (0x00, 0x00);
$NumOfSrcEl= 0x01;
@SrcEl= (0x00, 0xFF, 0x00, 0x84, 0x10, 0x00);
$NumOfDstnEl= 0x01;
@DstnEl= (0x08, 0x10, 0x00, 0x01, 0x01);
$Rsvd= 0x00;
@message= (@ADRDSTN,@ADRSRC,$MID,$MDLH,$MDLL,$SUBMID,@CHreq,@Pity,@Fla
+gs,@Timeout,@Level,$NumOfSrcEl,@SrcEl,$NumOfDstnEl,@DstnEl,$Rsvd);
$EM= 0xFD;


my $count=0;
$count += $message[$_] for 0..@message-1 ;
$count = 256 - ($count % 256);
$CHECKSUM=$count;
my @VPAP=($SM,@message,$CHECKSUM,$EM);

my $sock = new IO::Socket::INET (
                                        PeerAddr => 'localhost',
                                        PeerPort => '7070',
                                        Proto => 'tcp',
                                );
die "Could not create socket: $!\n" unless $sock;

print $sock @VPAP; 
close($sock);


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