Your 1983 Video Phone Is Finally Ready

February 7, 2024 by Al Williams 8 Comments

If you read Byte magazine in 1983, you might have expected that, by now, you’d be able to buy the red phone with the video screen built-in. You know, like the one that appears on the cover of the magazine. Of course, you can’t. But that didn’t stop former Hackaday luminary [Cameron] from duplicating the mythical device, if not precisely, then in spirit. Check it out in the video, below.

While the original Byte article was about VideoTex, [Cameron] built a device with even more capability you couldn’t have dreamed of in 1983. What’s more, the build was simple. He started with an old analog phone and a tiny Android phone. A 3D-printed faceplate lets the fake phone serve as a sort of dock for the cellular device.

That’s not all, though. Using the guts of a Bluetooth headset enables the fake phone’s handset. Now you can access the web — sort of a super Videotex system. You can even make video calls.

There isn’t a lot of detail about the build, but you probably don’t need it. This is more of an art project, and your analog phone, cell phone, and Bluetooth gizmo will probably be different anyway.

Everyone always wanted a video phone, and while we sort of have them now, it doesn’t quite seem the same as we imagined them. We wish [Cameron] would put an app on the phone to simulate a rotary dial and maybe even act as an answering machine.

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Schematics, For A Modern Flagship Phone

February 7, 2024 by Jenny List 36 Comments

The mobile phone is an expensive and often surprisingly fragile device, whose manufacturers are notorious for making them as difficult to repair as possible. Glued-together cases and unreplaceable batteries abound, and technical information is non-existent. But amongst all that there’s one manufacturer with a different approach — Fairphone. Case in point, they’ve released the full service guide including schematics for their flagship Fairphone 5.

Fairphone’s selling point is the repairability and internal accessibility of their products and of course they’ve made hay with this as a marketing opportunity. But aside from that, it’s a fascinating chance to look in-depth at a modern smartphone from the inside out. We see the next-level PCB layout and how everything is so neatly packed into the minimum space, all without resorting to a heat gun.

It’s great to have another hackable phone, and fair play to Fairphone for releasing all this stuff, but perhaps the most interesting part from where we’re sitting is how and where this phone is being sold. There have been hackable phones before, for many the Pinephone will spring to mind, but they have always been sold to an audience who buy to hack. Here in Europe where this is being written, the Fairphone is being sold as a consumer device. It won’t shake Apple or Samsung from their perches, but for a hackable device to be so generally available to those who wish to do things with it can never be a bad thing.

We took a quick look at Fairphone back in 2015, when they launched.

A Crossbar Telephone Switch Explained

February 4, 2024 by Jenny List 14 Comments

There’s an old adage about waiting hours for a bus only for two to appear at once, and for Hackaday this month we’re pleased to have seen this in a run of analogue telephone projects. Latest among them is the video below the break from [Wim de Kinderen], who is demonstrating the workings of a mechanical crossbar switch with the help of a vintage Ericsson unit and an Arduino replacing the original’s bank of control relays.

It’s possible everyone has a hazy idea of a crossbar array, but it was fascinating from this video to learn that the relays are worked by metal fingers being inserted by the bars into relays with wider than normal gaps between electromagnet and armature. This extra metal provides a path for the magnetic flux to actuate the relay.

The machine itself then is an extremely simple and elegant electromechanical device with many fewer moving parts than its Strowger rotary equivalents, but surprisingly we seem to see less of it than its American competitor. The video below the break is definitely worth a watch, even if you don’t own any analogue phones.

We recently saw a similar exchange implemented electronically.

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A Complete Exchange From Scratch For Your Rotary Dial Phones

January 29, 2024 by Jenny List 12 Comments

Such has been the success of the mobile phone that in many places they have removed the need for wired connections, for example where this is being written the old copper connection can only be made via an emulated phone line on an internet router. That doesn’t mean that wired phones are no longer of interest to a hardware hacker though, and many of us have at times experimented with these obsolete instruments. At the recent 37C3 event in Germany, [Hans Gelke] gave a talk on the analog exchange he’s created from scratch.

The basic form of the circuit is built around a crosspoint switch array, with interfaces for each line and a Raspberry Pi to control it all. But that simple description doesn’t fully express its awesomeness, rather than hooking up a set of off-the-shelf modules he’s designed everything himself from scratch. His subscriber line interface circuit uses a motor controller to generate the bell signal, his analogue splitter has an op-amp and a transistor, and his crosspoint array is a collection of JFETs. Having dabbled in these matters ourselves, it’s fascinating to see someone else making this work. Video below the break.

Have an analogue phone but nowhere to use it? Bring it to a hacker camp!

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POTS At A Hacker Camp

January 25, 2024 by Jenny List 1 Comment

For those of us off the Atlantic coast of Europe it’s a frigid winter as our isles are lashed by continuous storms. Summer seems a very long time ago, and the fun of the EMF 2022 hacker camp is an extremely distant memory. But the EMF team have been slowly releasing videos from the talks at that camp, the latest of which comes from [Matthew Harrold]. He was the force behind the public POTS phone network at the camp, providing anyone within range of one of his endpoints with the chance to have a wired phone line in their tent.

We’d love to imagine a mesh of overhead wires converging on a Strowger mechanical exchange somewhere on the field, but in a more practical move he used an array of redundant Cisco VOIP gear, and a multi-modem rack to provide dial-up services. Even then there were a few hurdles to overcome, but on the field it was definitely worth it as an array of unusual phone kit was brought along by the attendees. Our favourite is the Amstrad eMailer, an all-in-one phone and internet appliance from a couple of decades ago which perhaps due to its expensive pay as you go model, failed commercially. The video is below the break.

It’s a good time for this talk to come out, because it’s reminded us that the next EMF camp is on this summer. Time to dust off an old phone to bring along. Meanwhile, we’ve seen [Matthew] before, as he refurbished a sluggish dial mechanism.

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Remembering ISDN

January 15, 2024 by Al Williams 89 Comments

We are definitely spoiled these days in terms of Internet access. In much of the world gigabit speeds are common and even cheap plans are likely to be measured in 100s of megabits. But there was a time not long ago when a fast modem received at 56 kilobits per second. If you couldn’t justify a dedicated T1 line and you had a lot of money, you might have thought about ISDN – the Integrated Services Digital Network. [Tedium] has a great retrospective now that the UK has decided to sunset ISDN in 2025. ISDN started in the UK in the mid-1980s.

ISDN offered two 64-kilobit channels that could be bonded to reach 128 kilobits. There was also a slower third channel for commands and signaling (although you could use it for data, too, using an X.25-like protocol). If you wanted phone service, your voice was on one 64K channel and the data on the other. No need to tie up your phone just to get online. Voice was digitized at 8 kHz with 8 bits of G.711 encoding.

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37C3: When Apple Ditches Lightning, Hack USB-C

December 30, 2023 by Elliot Williams 11 Comments

[Thomas Roth], aka [Ghidraninja], and author of the [Stacksmashing] YouTube channel, investigated Apple’s Lightning port and created a cool debugging tool that allowed one to get JTAG on the device. Then, Apple went to USB-C for their new phones, and all his work went to waste. Oh well, start again — and take a look at USB-C.

Turns out, though, that the iPhone 15 uses the vendor-defined messages (VDM) capability of USB-PD to get all sorts of fun features out. Others had explored the VDM capabilities on Mac notebooks, and it turns out that the VDM messages on the phone are the same. Some more fiddling, and he got a serial port and JTAG up and running. But JTAG is locked down in the production devices, so that will have to wait for an iPhone 15 jailbreak. So he went poking around elsewhere.

He found some other funny signals that turned out to be System Power Management Interface (SPMI), one of the horribly closed and NDA-documented dialects owned by the MIPI Alliance. Digging around on the Interwebs, he found enough documentation to build an open-source SPMI plugin that he said should be out on his GitHub soon.

The end result? He reworked his old Lightning hardware tool for USB-C and poked around enough in the various available protocols to get a foothold on serial, JTAG, and SPMI. This is just the beginning, but if you’re interested in playing with the new iPhone, this talk is a great place to start. Want to know all about USB-C? We’ve got plenty of reading for you.