If you would like to purchase a non-Grace Digital branded USB to Ethernet adapter you can as long as it uses one of the following chips:
Realtek RTL8152: work only for the Mondo+ and Encore+
Realtek RTL8501: works for all new and legacy Grace Internet radios
Davicom DM9601: works for all new and legacy Grace Internet radios
Davicom DM9700: works for all new and legacy Grace Internet radios