For a lot of default passwords…
For default IP and also login info.
Otherwise, just google the manufacturer and model number for your router.
Please note that this won’t work for all routers. It will work on most Linksys routers, I imagine. The one shown is a WRT54G hardware revision v2.
It IS possible to use an AC adapter for Ethernet that uses the electrical system in your house instead of a long Ethernet cable. They are costly, though, and usually cause signal degradation, packet loss and high ping – in Layman’s terms, you should use a long Ethernet cable.
This video will show you how to use your older wireless router in conjunction with your new router (via a long ethernet cord to another part of your house) to boost your network’s wireless signal throughout your house. Note: You will have to end up with 2 different wireless networks BUT they are both on the same internet network for you to use for internet access. You will need to connect them via a long Ethernet cable from a client port on the first one to a client port on the second router. The 2nd router’s DHCP server will need to be turned off as the first router will be assigning local IP addresses and the second router MUST have the option to change from “gateway” to “router”, or a similar option, for this to work. On a standard linksys admin or configuration page, it is under “advanced routing”.