Build Your Own Dial-Up ISP – Now With Modem Pool!

When it was the only viable option, the screech and squeal of dial-up internet was an unwelcome headache to many. But now that its time has passed, it’s gained a certain nostalgia that endears it to the technophiles of today. [Doge Microsystems] is just one such person, who has gone all out to develop their very own dial-up ISP for multiple clients.

The retro network is based on an earlier single-device experiment, with a Raspberry Pi 3B acting as the dial-up server. It’s hooked up to four modems, three of which are connected over USB-serial adapters implementing hardware flow control.

Obviously, four analog phone lines are hard to come by in this day and age, so [Doge] uses Asterisk along with a series of Linksys SIP devices to create their own PBX network.  Each modem gets a phone line, with four left over for clients to dial in.

To connect, users can either call a certain modem directly, or dial a special number which rings the whole pool. Thanks to mgetty, each modem is set up to answer on a different number of rings to allow the load to be shared. Once connected, a PPP daemon handles connecting the user to the Internet at large.

While it’s unlikely we’ll all be ringing [Doge]’s house to get our next YouTube fix, owning your own dial-up ISP is certainly an admirable feat. We’d love to see it deployed in the field sometime, perhaps at a hacker conference or Burning Man-type event. Of course, if you’ve got your own old-school network pumping data, be sure to let us know! Video after the break.

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Run Your Own Phone To Bring The Dreamcast Back Online

Playing a video game online is almost second nature now. So much so that almost all multiplayer video games have ditched their split-screen multiplayer modes because they assume you’d rather just be alone at your house than hanging out with your friends. This wasn’t always the case though. In the early days of online multiplayer, systems had to rely on dial-up internet before broadband was readily available (and still had split screen if you didn’t even have that). Almost no one uses dial up anymore though, so if you still like playing your old Dreamcast you’re going to have to do some work to get it online again.

Luckily for all of us there’s a Raspberry Pi image to do almost anything now. This project from [Kazade] uses one to mimic a dial-up connection for a Dreamcast so you can connect with other people still playing Quake 20 years later. It’s essentially a network bridge, but you will need some extra hardware because phone lines use a high voltage line that you’ll have to make (or buy) a solution for. Once all the hardware is set up and working, you’ll need to make a few software configuration changes, but it’s a very straightforward project.

Granted, there have been ways of playing Dreamcast games online before, but this new method really streamlines the process and makes it as simple as possible. The Dreamcast was a great system, and there’s an argument to be made that the only reason it wasn’t more popular was that it was just slightly too far ahead of its time.

Thanks to [Rusty] for the tip!

How A Dial-up Modem Handshake Works

If you’re old enough to have used a dial-up modem we’d bet you can do an imitation of the sounds it made while connecting. Those not-so-beautiful sounds heralded the dawning of a technological era. But few actually know what each of those distinct sounds were doing. Now’s your chance to learn. This post explains each step in the dail-up handshake process.

This may be the most useful infographic we’ve ever seen. Normally we just seem them as gimmicks, but [Oona Räisänen] really put together something special with this one. Her blog post includes an audio clip so that you can play back the full handshake sounds. The main box on the graphic shows the audio spectrum from that clip, with an explanation below it. But you’ll also want to read through her full write-up for a more narrative description.

The part we found the most interesting is that these modems needed to disable the echo suppression used by the telephone system in order to operate at full-duplex. Apparently land lines disabled the speaker while you were talking so that you didn’t hear your own voice. This was a problem if the modem was trying to send and receive at the same time.

[via Reddit]