but this program takes 5 minutes to respond

The problem probably is that the device isn't sending a newline, so the <$sock> (i.e. readline) keeps waiting for it until the socket is finally closed — which is likely what is happening due to a timeout after those 5 minutes...

Try sysread instead (with a length value larger than the response you expect).

while ( sysread $sock, $_, 1000 ) {
        print $_;
}
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It could be that you need to send perhaps 128 bytes to it instead of a buffer ending in CRLF? Note: that CRLF is the network line ending, not just <LF>, so that part is right as far as it goes...However it could be that this thing is waiting for more bytes from you... Maybe..Send minimum 128 bytes? Read their spec..

Usually the smallest packet that will be sent is 128 bytes. Sometimes a 256 byte message will take a couple of packets even on the local machine.

Try just printing whatever the server returns to you on the first sysread() attempt. That will give you a clue as to what it is doing. If all you are expecting is less than 128 bytes, then you are probably done!

FYI, A Perl client read routine to get a 512 byte fixed packet might look like this:
my $buf = readn ($socket, 512);

sub readn
{
   my ($socket, $bytes ) = @_;
   my $offset = 0;
   
   my $buf = "";
   while ($offset < $bytes)
   {
      my $nread;
      my $nleft = $bytes-$offset;
      
      $nread = sysread($socket,$buf,$nleft,$offset);
      kill 'USR1',$$ unless (defined $nread);  ## undef is like -1 uni
+x return
      last if ($nread ==0);                    ## EOF
      
      $offset += $nread;
   }
   
  # print "length of received buff=",length $buf,"\n";
  # print $buf;
   return $buf;
}
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I have already read the spec , the device is a High Power Amplificator and i'm sending commands to another equipment that controls the HPA called controller,acording to the spec i have to send CR and LF so the controller can understand what i want ( in this case i want the output power level ) to be honest the specs don't have anything useful about the communication.

The lenght of the pakage that i receive is 131 bytes ( it sends 2 pakages one with 63 bytes and another with 68 bytes i'm using wireshark to trace the pakages)

i used Eliya solution and I still have a big delay

Here is the answer of my program

&#9824;A?42.3< 30D 0.111.3&#9829;) 210 Seconds Delay
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Changed 1000 to 131 and 2000 but still no fast response

while ( sysread $socket, $_, 131 ) { # 2000 , 1000
print $_;
}
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