Plenty of rotary and touch-tone phones still work fine. What they lack is a line to plug into. Analog Redial, an open-source project from Scott Dylewski, is a small board that provides one. It gives one or two analog phones dial tone and ringing, lets them call each other, and can bridge them to VoIP. You can also dial a number to fire an automation. Hackaday covered the project on November 2, 2026, and the full design is on GitHub.
Dylewski's Hackaday.io project page was created on October 12, 2026. It calls the system "a hackable analog telephone system," and that is a fair description. The hardware is in KiCad and the firmware is written in C on ESP-IDF under the MIT license. There is a serial console for poking at it, and the design files are published.
What is on the board
According to Hackaday's write-up, an ESP32-C6 "does all the heavy lifting," working with an ES8388 audio chip. The project README lists the main parts as the ESP32-C6, the audio codec, two phone line interfaces, and a separate Bluetooth module board built around a BM64. The sources do not give clock speeds or a full electrical specification for the design, so we don't either. Check the KiCad files in the repository for the electrical details.
The board supports both kinds of dialing a vintage phone collection will need. The README covers rotary pulse dialing and touch-tone dialing, so a rotary set and a push-button phone can sit on the same system. The second line is optional. Per the README's cost table, it adds about $10 to a build.
What it does
The README lists these features:
- Offline calls between the two phones. Two handsets on the same board can call each other with no Wi-Fi. The default code is 321, and it is configurable.
- VoIP through a SIP server. The README names Asterisk and FreePBX and says any SIP server will work. That lets an old phone register with a home PBX or reach an outside VoIP service.
- Board-to-board calls over Wi-Fi without a server. Two Analog Redial boards on the same network can call each other directly. No PBX needed.
- Dial codes up to 10 digits. Dialed numbers can trigger actions, not just calls.
- Home Assistant integration over MQTT or webhook, which the README marks as experimental. Hackaday describes this as dial codes that can control Home Assistant.
- An answering machine, listed by Hackaday among the system's functions.
- A web UI for configuration, plus the serial console mentioned on the Hackaday.io page.
The Bluetooth board is the odd one out. Hackaday says it lets you use a landline phone as a handset for a smartphone. The README describes the bell ringing for incoming calls, lifting the handset to answer, and dialing out on the rotary dial. It is optional, and the README puts it at about $15 extra.
From Raspberry Pi to ESP32
This is not the first version. The Hackaday.io page says the original Analog Redial ran on a Raspberry Pi. Dylewski says the ESP32 version has more features and is cheaper to build. He also compares it with a Grandstream VoIP adapter, the kind of off-the-shelf analog telephone adapter (ATA) people use to connect a landline phone to a SIP service. His argument on the project page is that on a Grandstream device you need to dial *47 and then the other phone's address, which is "not exactly simple," while Analog Redial is a whole phone system on its own that you can hack and extend.
The comparison helps explain who the board is for. Analog Redial covers the same SIP use case, then adds things the README highlights: direct phone-to-phone calls with no server, rotary dialing support in an open codebase, an answering machine, and dial codes that can trigger home automation. Because the firmware is MIT-licensed C on ESP-IDF, you can change that behavior yourself.
Build and parts
The README says no surface-mount soldering is needed: the fab places the small parts, and everything you solder is through-hole. Per Hackaday, most of the board can be ordered pre-assembled from a board house. The README's split is a JLCPCB-assembled PCB plus through-hole parts bought separately from DigiKey and soldered by hand.
The README's cost breakdown, from October 2026, in US dollars and including shipping and import tariff:
- Assembled PCB from JLCPCB: $17.11 per board (5-board minimum order)
- Through-hole parts from DigiKey: about $19
- DigiKey shipping: about $1 per board
- Total, one phone line: about $37 per board, or about $186 for five
- Second phone line: +$10 per board
- Bluetooth board: +$15 per board
A one-line build therefore costs about $37 per board. The catch is the five-board minimum: the README says one board works out to about $110 up front, with four spare PCBs. Board-house and distributor prices change, so treat these as the creator's October 2026 snapshot, not fixed prices.
Phone lines carry real voltage. The README warns that the board drives about 48 V DC on an off-hook line and about 60 V AC while ringing, and says never to connect it to house or telephone-company wiring. It is a hobby project, not certified telecom equipment.
Analog Redial is not a finished product on sale. The README links an interest form for pooled group orders, but it does not describe a store listing, a pre-order or a crowdfunding campaign. It is an open-source design that you build from the published files.
What It Means for Makers
The obvious audience is anyone with a working old phone that has nowhere to plug in: collectors, people restoring rotary sets, and anyone who wants a real bell ringing in the kitchen again. It should also appeal to people who run their own Asterisk or FreePBX server and want an open, scriptable analog endpoint. Home Assistant users get an unusual input device, a rotary dial that can trigger automations, though that integration is still marked experimental. Educators get a working phone system with published schematics, C firmware and a serial console, which could make a good teaching platform for how signaling and audio paths work.
For some of these uses, the board is an alternative to a commercial VoIP adapter such as the Grandstream unit Dylewski cites. It also offers features the README lists that go beyond a plain adapter: serverless calls between phones and between boards, an answering machine, a web UI, and the Bluetooth handset option.
Status and pricing, as the sources give them: Analog Redial is an open-source design (KiCad hardware, MIT-licensed ESP-IDF firmware), available on GitHub to build yourself. It is not a commercial product. The README estimates about $37 per board in US dollars as of October 2026, based on a five-board JLCPCB order at $17.11 per assembled PCB plus about $19 of DigiKey through-hole parts and about $1 of shipping. That works out to about $186 for five boards. The second line adds about $10 and the Bluetooth board about $15. Builders who want the Home Assistant features should keep in mind that the README still labels that integration experimental.
