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Comment by apetresc | Hacker News Reader

I'm not too well-versed in hardware - is it really that easy to swap out a 2G modem with a 4G modem and have it "just work" without touching the drivers? Even if the baseband/modem chips miraculously do conform perfectly to some I/O protocol at the hardware level despite being multiple generations apart, wouldn't the difference in timings break whatever firmware the Nokia 5110 has, which was expecting only a single very specific hardware configuration? Or is the author planning to also hack the drivers?

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These phones didn't have the modern smartphone architecture where there are separate CPU cores for the user OS and the modem. It's one single CPU core that does both the UI and all the low-level stuff required for communication with the tower. They were going to replace the board that contains that CPU and all the radio circuitry with one they were going to design from scratch around that 4G module.

No, it's like reusing keyboard and monitor for a new PC. This phone uses those parts fully separated from the computer part that the author argues it should be possible to remake just the host computer part to recreate the experience.

4G doesn't even have a proper voice call support, and substitutes that with a carrier grade Discord type thing called VoLTE(oversimplification). Zero chance old firmware could work.

> 4G doesn't even have a proper voice call support, and substitutes that with a carrier grade Discord type thing called VoLTE(oversimplification).

That "carrier grade Discord type thing" is more or less standard SIP VoIP, just over a prioritized data channel similar to how DOCSIS has PacketCable which is more or less MGCP VoIP over a prioritized data channel.

It's absolutely proper voice call support, the majority of calls you make or receive in 2024 have been connected over SIP at some point along the path.

> Zero chance old firmware could work.

The sorts of modules like the author was proposing using can be interacted with over relatively standard AT commands, so it's actually plausible that if there were a separate application processor it might be able to perform basic functions like placing/receiving calls without any firmware changes. The module handles all the VoLTE stuff and just exposes it as if it were any other modem.

That said it's not uncommon for "dumbphone" type applications to run the application code on the baseband processor, in which case obviously it's incredibly unlikely that this new module is even a related family of processor, much less compatible with existing code.

>That "carrier grade Discord type thing" is more or less standard SIP VoIP, just over a prioritized data channel...

It is completely restricted to one SIP provider. Which raises an interesting idea for improved competition. Make it possible for the user to choose their SIP provider. Force the phone companies to allow the use of that priority to any SIP RTP stream and otherwise make those companies just sell data service.

That would make a project like the one in the linked article come down to getting a magic module that provided an internet connection...

It's not proper call support because the standardisation is a mess. Some carriers don't even support it until now, many refuse to allow it on phones they did not sell etc.

It should have been in the standard from the get go, strictly defined so there's no different standards to check and certify. They should all work the same so there's no need for that.

The lack of standardisation is causing huge problems in countries deprecating 2G and 3G like Australia where people have to throw away perfectly good phones because they're not VoLTE capable according to their provider (and the government mandating that phones without voice service must be banned)

Just like 2G and 3G.

No. This phones keypad , controller, and screen are on a separate board.

This would be like plugging your monitor and keyboard into a new computer.

There are some lorawan handheld communicatiors using surplus blackberry cases and keyboards from blackberries that never were, that they got for pennies.

Except this dude wants to drop in a roll-your-own cellphone board with a basic os, instead of a lorawan radio and basic os. Same idea. But he will have to design this.

Whereas You can get schematics to build a lorawan communicator with blackberry parts, and there are community supported roms for that

Your reply is less insightful than the original commenter.

I think the idea here is to basically create a new phone, but use the original case, buttons and display.

I just wish I could buy a phone that has the same look and feel (sound, screen, etc.) as the 5110, is compatible with modern networks, and has a modern battery.

As a sibling says, this likely won't work for a Nokia feature phone, because it's an integrated design and there's no separate modem.

For a design with a modem module and a ux module, it might possibly just work to swap things out, but it would depend on how VoLTE is supported. If that is all managed by the modem module, then you're probably good.

These modem modules are generally a serial port that speaks Hayes (AT) protocol. Plus some analog lines for mic and speaker. Some 4g modules might be serial over USB and may leave VoLTE entirely up to the application module, that's going go look different.

Some of the modules are a qualcom SoC that runs headless Android. Which works, I guess, but seems bizarre.

No, of course not. That's why this article is two years old without an update.

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