what you asking to do is create a null modem connection (modem to modem). i doubt the dreamcast support this without using some external support of software. you can't dial in directly connected to the modem because there is no dial tone. the RJ11 port on your eMac is a modem port you know that right? the RJ45 port is your ethernet. how are you expecting to get information from the Rj11 or the RJ45? your question is not grounded in any technical sense what so ever. you seem to suffering from what i call the magic wand syndrome. you seem to want to technology to do something for you and yet you have no clue how it works or what you really want from it. to cure this, open your web brower and goto google.com and search for dreamcast hacks. i still don't know why you want to connect to your dreamcast. what are you hoping to find?