These are the dreamcast ethernet cards so you don't have to use the modem to play online.. :-)
To: port-dreamcast@netbsd.org
Subject: Lik-Sang BBA Stock
Looks like Lik-Sang have some more official BBA's in stock, but they
tend to run out *very* fast so act quickly:
http://www.lik-sang.com/catalog/news.php?artc=2408