What kind of operating system do you have?

I'm lost in this thread too many informations for me. Firstly, do you have access to your router settings by internet browser? What kind of model W8960N do you have (hardware version)? You have to...

Do you have public IP address on WAN port? Please check it in status tab on TP-link.

Of course use the same cable directly to my PC is working fine. Do you mean about forwarding too?

Firstly, do you have public IP address on WAN port? Secondly please change web management port of your router in Remote Management tab.

So you know that ADSL line needs modem or router with modem?