The Smallest Dialup ISP Is A Raspberry Pi And A Prison Phone

April 4, 2026 by Tyler August 25 Comments

There were a plethora of tiny, local ISPs in the days of dial-up internet. Along with the big providers, many cities would have more than one. Some of those have survived broadband, but none of them were as small as [Jeff Geerling]’s Pi ISP — a tiny dialup ISP built so his Aunt’s old G3 MacBook can get online at 36kbps, as God and [Robert Kahn] intended.

Hardware-wise, the Raspberry Pi is at one end of the chain, and your retrocomputer at another. In between, you’ll have a USB modem plugged into the Pi, and a device called a “two-way line simulator” to create a dial tone for that plain-old-telephone goodness. [Jeff] notes that these were commonly used in prisons for the phones that visitors use to talk to inmates.

Of course, since these devices are designed strictly for voice transmissions, which POTS was built for, you’re not going to get over 36 kbps, and that’s even with high-quality gear. The cheaper options might drop you down to 28k… just like with an ISP back in the day. ‘You get what you pay for’ is very rarely false.

Now, you can use this technology to just connect two computers together — as we’ve featured previously — but [Jeff] has gone the extra mile to put together, via Ansible, an easy-to-install software package that will let the Raspberry Pi act just like your ISP’s servers once did, and connect you to that series of tubes once called the World Wide Web. Of course, the World Wide Web isn’t built for dial-up anymore, so you’re going to be waiting… a while. Hackaday’s front page isn’t especially heavy, weighing about 4MB at the time of this writing, but that’s 15 minutes of load time, and you still aren’t reading the articles.

You also won’t be able to access much on old machines that can’t do HTTPS, but [Jeff] thought of that and bundles [rdmark]’s MacProxyClassic to translate the modern web into HTML tags that Netscape can understand and serve them over HTTP. You’ll still be waiting for our modern bloat, but perhaps not quite so long.

If you want the “authentic” dial-up experience, you’ll need to see the lightweight webpages of Yesteryear, and MacProxyClassic contains a Wayback Machine extension for that purpose. We featured a similar project a while back that did that, but without all the joys of dial-up. Now get off the computer, we’re expecting a call!

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

May 30, 2020 by Zoe Skyforest 54 Comments

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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