What is needed to connect Ethernet and internet through a DSL or cable modem?

First you must have an internet service provider and it then depends on what equipment they have provided. An ethernet cable will connect to a modem or a router and go to the device for a wired connection. I used a Cat 6 ethernet cable and a router to split the signal from my first cable modem to a router and then from my PS3 and PC connected 2 more ethernet cables to the back of the router. Later Comcast sent a gateway modem and that already had WiFi and more than one spot to plug in the ethernet cables and I put my router away