PHP fputs和fsockopen

I'm a .net developer and this piece of PHP is really confusing me....

$ptr=@fsockopen(T_HOST,T_PORT,$errno,$errstr,T_TIMEOUT); 
if($ptr)
        {
//--- If having connected, request and collect the result
         if(fputs($ptr,"W$query
QUIT
")!=FALSE)
           while(!feof($ptr)) 
             {
              if(($line=fgets($ptr,128))=="end
") break; 
              $ret .= $line;
             } 
         fclose($ptr);

If T_HOST is 123.100.98.209, T_PORT is 443 and $query is "QUOTES-EURUSD", what kind of request does this piece of code produce?

While this PHP code does return something, when I try "http://123.100.98.209:443/QUOTES-EURUSD" from the browser and postman, it just fails.

What's

" QUIT "

doing in the query string?

And what does the "W" mean in front of the $query?

Sorry if these questions are too basic, I know nothing about PHP.