Hey TaoOfThe777. I have a Linksys like TheTech is referring to.
Ethernet doesn't have an "IN" port. You simply have two connections on the wall plate you're talking about - one is A and the other is B.
Ethernet uses 4 wires of an 8 wire cable to communicate. 2 wires in each direction - 2 Transmit, 2 Receive.
A router is used to "route" traffice from one network to another. In your case, you would have an internal network - probably 192.168.1.0/255.255.255.0. When you try to get out on the i'net, the router will see that traffic isn't bound for your network and will "forward" the traffic to the appropriate port - the one connected to your DSL "router".
Check this out for more info:
http://www.linksys.com/Products/prod...rid=23&prid=20