Ethernet/Airport. ADSL sends broadband over the phone line. Router has an ADSL modem in it which filters the broadband signal out.
I'm fighting the temptation to try AOL for the hell of it! I'm old enough to remember the early days of the internet over a 28.8k modem... Broadband was revolutionary when we got in in 2000.
internet in the us has actually been around since the 80s and it use to be FREE