Hi friends, this is a small guide which i made myself for port forwarding on your DLink DSL 502 T Routers.
Login into your modem through 192.168.1.1 and go to "Advanced" Tab.
Select "Virtual Server" from the side tab.
There, select the "users" button, and click Add. There specify the name etc. (can be whatever you like) and specify the port number you want to un-block.
After adding the rule, restart your router, again go to the virtual server page and add the rule to "Applied Rules" and click apply and then again restart you router.
Now you are done!

For noobs, port forwarding is one to open up a port for your torrent clients to download stuff by allowing incoming connections.