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.

Mailblocks Makes Your Phone Work More Like The Post, Kinda?

December 23, 2023 by Lewin Day 3 Comments

Phones can be distracting, with notifications popping up all the time to snare our attention and maybe even ruin our lives. [Guy Dupont] wishes to be no slave to the machine, and thus built a solution. Enter Mailblocks.

The concept is simple. It’s a physical mailbox which [Guy] can put his phone in. All notifications on the phone are blocked unless he puts his phone into the box. When the phone is inside and the box is closed, the little red flag goes up, indicating “DOPAMINE” is available, and [Guy] can check his notifications.

To achieve this, [Guy] is running a custom DNS server. It redirects all the lookups for push notifications on Android so they go nowhere. Placing the phone in the mailbox turns the re-directions off, so the phone can contact the usual servers and get its notifications as normal.

It’s a novel way of fighting against the constant attention suck of modern smartphones. Rather than being bombarded by notifications in real time, [Guy] instead has to take a significant intentional physical action to check the notifications. It cuts the willpower required and the interruptions to his work in a fell swoop.

We’ve featured [Guy’s] innovative and outside-the-box projects before, too. His smart pants were an absolute tour de force, I might add.

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What Can You Do With Thousands Of Vintage Telephones?

November 20, 2023 by Dave Rowntree 56 Comments

Telephones. We’ve got a few around the place, and some may remember all the weird and wonderful varieties produced over the years. But, vintage phone dealers [Ron and Mary Knappen] may have a few too many. With a large 41,000 sqft property, at least three farm buildings, and no fewer than 33 semi-trailers loaded to busting with racks of phones, the retiring couple have a job sorting it all out and finding someone passionate enough to take over this once-strong business.

Technology has moved on somewhat since 1971 when they got into the retro business, and there are only so many period dramas being produced that could make a dent in a collection of a thousand steel desk phones. Nobody seems interested in taking on their business, so they are concentrating on emptying that large property in order to sell it, but the fate of the crazy number of other storage locations seems uncertain. Perhaps, other than a few museums around the world purchasing a few, this collection really is likely heading to the recyclers.

So what can we do with a vintage phone in this modern era? Here’s a primer to get you started. How about going cellular? Or maybe just add them to your existing designer collection?

Thanks to [Jeremy] and Adafruit for the tip!

A Buzzing, Flashing Phone Ringer For The Elderly

October 11, 2023 by Kristina Panos 8 Comments

For a lonely person, elderly or otherwise, the sound of a ringing phone can be music to the ears, unless of course it’s another spam call. But what good is a phone when you can’t hear it well enough to answer?

[Giovanni Aggiustatutto] was tasked with building an additional ringer for a set of cordless landline phones belonging to an elderly friend. Rather than try to intercept the signal, [Giovanni] chose to simply mic up the phone base that’s connected to the phone port on the router and send a signal over Wi-Fi to a second box which has a loud piezo buzzer and a handful of LEDs.

At the heart of this build is a pair of ESP8266 Wemos D1 minis and an Arduino sound sensor module inside a pair of really nice-looking 3D printed boxen that may or may not have been inspired by an IKEA air quality sensor. On the receiving side, a green LED indicates the system is working, and the red LEDs flash as soon as a call comes in.

All the code, schematics, and STL files are available for this build, and between the Instructable and the build video after the break, you should have no trouble replicating it for the hard-of-hearing in your life.

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Grannophone Helps You Stay In Touch

September 10, 2023 by Kristina Panos 20 Comments

Whether it’s distance, pandemics, or both that separate you from your elderly loved ones, what’s the best idea for communicating with them so they don’t suffer from loneliness on top of issues like dementia? We’d say it’s probably something like [Stefan Baur]’s Grannophone.

Back in late 2020, a Twitter user named [Nitek] asked the Internet what could be done in the way of a grandma-friendly video-conferencing solution, provided Grandma has a TV and a broadband internet connection. At first, [Stefan] was like, just get her an old iPad and FaceTime with her. But the question got him thinking. And prototyping.

Grannophones are essentially Linux machines with a video-capable SIP client connected over a VPN for privacy reasons. In simple mode, picking up the handset of one Grannophone will call the other, but more complicated configurations are possible. We particularly like that replacing the handset automatically obscures the camera. That’s a nice touch.

At this point, the Grannophone is a work in progress. The idea is that they be extremely easy to build at the kitchen table, like on the order of disposable Swedish furniture. If you can contribute to the project, please do. Be sure to check out the demonstration video after the break.

On the other hand, if Granny is 1337, you could always video-conference in terminal.

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Portable 1990s POS Will Strain Your Back

August 13, 2023 by Chris Lott 4 Comments

[JR] over at [Tech Throwback] got ahold of an unusual piece of gear recently — a portable Point of Sale (POS) credit card machine from the late 1990s (video, embedded below the break ). Today these machines can be just a small accessory that works in conjunction with your smart phone, but only the most dedicated merchants would lug this behemoth around. The unit is basically a Motorola bag phone, a credit card scanner, a receipt printer, a lead-acid battery, and a couple of PCBs crammed into a custom carrying case

Despite having a lot of documentation, [JR] struggles to find any information on this U.S. Wireless POS-50. He finds that the credit card scanner is an Omron CAT-95 authorization terminal, and the Motorola SCN-2397B phone appears to come from the Soft-PAK series.

He is able to power it up, but can’t do much with is because he is missing the authorization password. But regardless, with the demise of the Advanced Mobile Phone System for over a decade, this 850 MHz band analog phone can’t connect to the network anymore.

If you happen to know anything about this old POS, or used a similar luggable system for accepting credit cards in the 1990s, let us know in the comments below.

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