The page of all things 
NewtonEthernet.
also see EthernetCards
Historical rambling follows:
Ethernet was a 3 megabit per second networking protocol that ran on very expensive large 52-Ohm coaxial cable, which was called "yellow hose" because it looked like a yellow garden hose strung through the ceiling. Adding new stations was exciting because it was usually done with a so-called "vampire tap", in which one inserted a probe through the side of the jacket, through the insulating sheaths, finally contacting but hopefully not severing the center conductor. Occasionally the network was shorted out by this operation, necessitating cable replacement.
Ethernet migrated to 10Mbps along with its commercial acceptance in the early 1980s, as well as to RG-58 52-Ohm coax, aka "thin net" or 10base2. The early 1990s brought us ethernet on twisted-pair "telephone wire", commonly known as 10baseT.
In 1996, the new thing was 100 megabit ethernet, called "100baseT". Fortunes were made and lots of new gear was bought.
In 2002 the hot happening technology was gigabit ethernet.
To you, the average Newton user, the best thing to come out of these speed boosts has been the massive price drops in the old 10Mbps ethernet gear, which your Newton will never ever be able to outpace.
