“Just turn it off” and Airplane Mode | Hacker News Reader

“Just turn it off” and Airplane Mode

refugeprivacy.com

10 pointstranspute10 comments

If you really want devices you can turn off, you may want to back the EU initiative to return to a time of replaceable batteries. Because, even when "off" in the colloquial sense, some devices remain "on" in the real sense: they have small amounts of function, in the "off" state sometimes.

I don't mean the battery backup RTC. I mean that in order to do things like "wake on lan" they simply have to be partially "on" in some ways. Colloquially they are off. They are not electrically off, or isolated from functional systems which know how to do some things.

(obviously, phones do not normally expect to be connected via RJ45 into a network which implements the wake-on-lan and IPMI)

If you remove their main batteries, they become much more really "off" -if you don't have an external source of power attached.

I still don't entirely understand how HDMI/CEC knows what my monitor is. It feels like the monitor is powered off, does the chipset respond to the voltage sent "up" the HDMI lead?

> If you really want devices you can turn off, you may want to back the EU initiative to return to a time of replaceable batteries.

Just to clarify, the EU initiative isn't for the 90's style batteries you can just carry 5 with you and swap when they run out. It's purpose is to make swapping batteries not require special tools like pentalobe screwdrivers or specific tools to heat components.

> I still don't entirely understand how HDMI/CEC knows what my monitor is. It feels like the monitor is powered off, does the chipset respond to the voltage sent "up" the HDMI lead?

Yes. The HDMI source provides 5V over pin 18.

The same mechanism is also used in VGA and DVI.

This is a poorly concealed advertisement for a "Faraday sleeve", rife with misinformation.

No, cell phones do not communicate with cell towers while powered down. This is fairly easy to verify, and it's telling that the screenshots used as proof have deliberately had all attribution removed...

iPhones do communicate with others over Bluetooth; they explicitly warn you of this when turning your phone off.

As a side note, confirming no connections with cell towers is not “fairly easy to verify”, it requires a fair bit of semi-specialized gear.

> As a side note, confirming no connections with cell towers is not “fairly easy to verify”

It's fairly easy by comparison with more detailed questions about cellular traffic like "is this bit of specific data being sent to a cell tower". It does require some RF test equipment and the know-how to use it, but no specialized knowledge beyond that -- in other words, the sort of thing a company selling a RF-blocking device should have access to.

I have never seen this warning. What does it say? Do you have a screenshot or link about it?

https://www.apple.com/icloud/find-my/

“You can even find devices that are offline or powered off.“

There’s some technical details there. The key words are “Find My Network”

When you power a newer iPhone off, there's a small message under the "slide to power off" switch, with the text:

> iPhone Findable After Power Off

Tapping it displays a dialog box with a longer message:

> iPhone Remains Findable After Power Off

> Find my helps you locate this iPhone when it is lost or stolen, even after power off

> The location is visible in Find My on your other devices and to people in Family Sharing you share location with.

> You can temporarily turn off Find My network and it will resume when this iPhone is turned on again.

with buttons "OK" and "Temporarily Turn Off Finding".

Peculiar.

Back in the times of GSM/2g, and the fable 3310, roaming was EXPENSIVE on Europe.

So, before going to Spain, I would turn my Nokia off.

After returning to my country, and well inside the country away from any Spanish antenna, I would turn on the device.

And every time, I would get a SMS informing me of the roaming costs.

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