brourke228 posted a tutorial on how to get online with your Dreamcast by extending your LAN over a phone line to your Dreamcast.
I've been working on this for a while now and finally got it set up correctly. Through this method you will be using a network device (Netopia R2000/R2020) to automatically accept Dreamcast's modem calls and extend your LAN over a phone line (to Dreamcast). The end result is that you will have Dreamcast on the same subnet as all other devices on your broadband network, it will have internet (obviously), and all port forwarding etc. will be dealt with right on your broadband router just as with your computers. Essentially your broadband router will not be able to tell the difference between this and a BBA.
This is not the cheapest setup, but if you can find the materials for a good price then it's totally worth it. Since this method of connection is completely seamless to connect like a bba, but allows you to connect to anything since it's still using dial up.
Here is what you need to set this up:
-Router (any broadband router should do)
-Phone Line Simulator (I'm using a Teltone TLS3)
-Dreamcast w/ 56k Modem (Model A and B will both work)
-2 Telephone cords (If connecting two Dreamcasts simultaneously you will need 4 telephone cords, and 6 for three simultaneous Dreamcast connections)
So onto the features of this connection method:
-19Kbps connection speed
-130ms latency (over LAN)
-No phone line is required
-Dreamcast will be on the same subnet as PC's on your network (ie, if your router is 192.168.1.1, then Dreamcast can be anything from 192.168.1.2 to 192.168.1.255)
-As a result of being on the same subnet, it is managed completely by your broadband router as with all modern network devices ( You can even put Dreamcast in DMZ if you so choose)
-The Netopia R2000/R2020 will automatically answer Dreamcast's call
-This works with model A and model B Dreamcast Modems both without the use of a line voltage inducer
-The phone line simulator will supply the dial tone for Quake 3 and any other game which does not support blind dial
-You can connect 2 (3 if you attached a serial modem) Dreamcasts simultaneously so long as there are sufficient lines on your phone line simulator.
-Because Dreamcast is seen on the same subnet as other PCs on the LAN, you can use drdns and connect to PSO using the same method as a BBA without the need to use a codebreaker or autoconnect disc.
[...]I have tested PSO, Quake 3 Arena, Max Pool, 4x4 Evolution, and StarLancer. With 4x4 Evolution, Max Pool and StarLancer it sometimes takes a couple tries for it to connect. If the Netopia router does fail to answer a call, wait for the Channel and Ready LEDs to go out before attempting to redial. Once the game is connected you should not have any issues.
Read the full tutorial here: http://dreamcast-talk.com/forum/viewtop ... f=3&t=3122