For example, the response
OFST -0.75

##</code><code>##

 
810100000000000c4f465354202d302e3037350a

##</code><code>##

 
VDIV 0.05
810100000000000

##</code><code>##

 

#!perl -w

use strict;
use IO::Socket;

my $verbose = 1;
print "===\n";

my $host = "127.0.0.1"; # or whatever
my $port = 1861;

my $remote = IO::Socket::INET->new( Proto    => "tcp",
                                 PeerAddr => $host,
                                 PeerPort => $port)
or die "Couldn't connect to $host:$port\n$!\n$@\n";

my $msg = 'ofst?';

# send query
$remote->send(wrap($msg))
    or die "Couldn't send: $!\n$@\n";

# read the remote answer
my $answer = <$remote> || '---';
print "answer: =$answer=\n";

my $response = unwrap($answer);
print "response: =$response=\n";

close $remote;

exit;


sub wrap {
	my ($data) = @_;
	my $header = pack "C4N", hex '0x81', hex '0x1', 0, 0, length($data);
	return $header . $data; 
}

sub unwrap {
	my ($packet) = @_;
	my ($op, $hvers, $count, $data);
	($op, $hvers, undef, undef, $count, $data) = unpack "C4NA*", $packet;
	{
		my $warn = '';
		my $length = length($packet); 
		if ($count != $length) {
			$warn .= "warn: $count != $length: \n";
		}
		$warn .= unpack "H*", $packet;
		print STDERR "$warn\n" if $verbose;			
	}
	return $data;
}
__END__