USB to Ethernet?

[aceizace]

I recently bought a broadband adapter for my gamecube. However, my dsl modem does not have any ethernet ports on it. I've been told by a friend that i can get something to make the usb socket on the modem 'into' and ethernet port. If you look on a normal usb cable, the end that plugs into the device (not computer) is what my modem uses, i have looked on the internet but can't find anything, only ethernet to computer via usb for networking. Can anyone point me in the right direction? Thanks!

[j2buttonsw]

I think they are different technologies. Nintendo thinks this also: http://www.nintendo.com/online/buy_bba.jsp