It really depends how your computer(s) connect to Broadband. In the early days most people had what I will call a Broadband modem which allowed just one computer to connect to the telephone line via Broadband. Nowadays a lot of people have a modem/router which allows multiple computers to connect usually with a Wireless option as well.
If you can identify the make/model of the box that connects you to Broadband we might be able to provide further advice. Be aware thar there are also different flavours of 'Wireless' so we'll need to check out the specifications.