sub read_data {
    # accept data from the socket and put it on the queue
    my( $qin, $qout, $socket ) = @_;
    while ( 1 ) {
       ## Don't enter a read state until your pretty sure there will be something
       ## to fetch. The loop count (10) x the sleep value (1) define the device 
       ## data frequency
       for( 1 .. 10 ) {
             ## if there are any commands pending, send them to the GPS device
             while( my $cmd = $qin->pending ) {
                print $socket $cmd;
            }
            sleep 1; ## or usleep 0.1 or 0.01 etc. 
            ## depending upon the urgency of your cmd requirements
        }
        my $data = <$socket>;
        last unless defined $data;
        print "$data";
        ## Process data from connected devices
        $qout->enqueue( time . ' ' . $data );
    }
    shutdown $socket, 2;
    close $socket;
}