Can your cell phone be used to track you when it is turned off? One of the many articles out there about the recent story on data mining and phone logging stated this quite clearly.
Is this true or not?
I believe they mean the screen is turned off and you’re not talking on or using the phone, and yes they can be tracked because it’s still communicating to the cell tower.
No, the wording indicated powered down. That was what confused me.
Fortunately, I use an Android phone and can in face remove the battery when I do not want the phone to be able to send any signals. But- is it sending signals of any kinds while powered down?
The article does not cite a source and I do not have a more authoritative cite. However, as far as any electronic devices go, being “turned off” means whatever the engineers decided that it means when they designed it. If they decided it means, “The user cannot perform any useful functions but the phone will continue to send GPS and other data to cell towers,” then that is technologically possible. I don’t know what the rationale would be for doing so. It would clog up bandwidth with information that doesn’t seem useful to the user or to the carrier.
Read the comments on that article. I think the author is confused about a turned off phone pinging cell towers, which would be the only way to track a phone. The GPS receiver doesn’t send any information when it’s working, it’s just a receiver.
I know that they can tell what your location was just before you turned it off.
A cell that is “off” as in “waiting for an incoming call, screen dark” still checks in with (pings) the nearest cell tower every few seconds. The give-away is that your battery still drains over time.
A cell powered down - as in all systems off, battery power is not being drained, etc - is a dead lump of metal, gives no more indication of life than a paperweight. Of course, as soon as it is booted, it checks in and the authorities can find it. iPhones can be powered down, and as a result are really “off”. You can tell because they do not use up the battery when powered down.
A cell without a SIM card (those that use them) does not have any instructions on which company network to contact, so it is also not talking to any system. (In The Following Bacon and others eem to delight in pulling and crushing SIM cards when they are not destroying the whole phone. Once the card is pulled, it has no power it does not need to be crushed to avoid tracing - just don’t put it back in the phone. )
Both the phone and the SIM have unique numbers, so when you use one in the other, the phone company (and hence police) can find you.
A cellphone can continue to operate when turned “off” by the user, because “off” might not be off in the sense of “off” as used by the average Joe.
Whether it does continue to communicate, I can’t say. So if you are paranoid, you will remove the battery if you want to be absolutely sure. Otherwise, you will always be wondering.
Oh, I’m as paranoid as the next Doper. 
Just found it entirely possible that when powered off, a device wasn’t really powered off.
Modern-day television sets are a good analogy. When you hit the On/Off button on your remote, you are not turning your telelvision off. Not hardly. You’re blanking the display. This saves the hours of burn on the monitor but in fact the television is still fully powered on.
For many sets, losing power means losing an immense array of programmed choices, channels and features. They’re not meant to lose 100% of power. As is the case with your average cell phone or iPod charger that is left plugged in, modern day television sets are immense power vampires. When “off” and not in use, they continue to drain.
Yeah. I admit it. I lean over and yank the plug when going out for the day and certainly before leaving town on a trip. I kill the television, DVD and VCR ( old school !! ) and also unplug the WiFi and some chargers.
It may save me a few dollars on the ConEd bill, but I’m making my small effort towards reducing the vampire electric device drain.
Anyway, t.v. sets aren’t really off. I wondered if this applied to cellular phones.
ETA: We don’t have cable t.v. and therefore have no DVR or similar device. The channels are remembered in the chipset on the t.v. Killing power does nothing to its ability to manage the through-the-air channels.
Just so you know, most TV sets these days use very little power when off - last time I was shopping for a TV, they were mostly 0.2 Watts when in standby. All they really do is keep the IR receiver going so you can turn them on with a remote. 0.2 Watts over an entire year is 1.7 KWh, which costs me about a quarter.
Information like channels, video & audio settings, etc. is kept in persistent memory - probably a cheap NAND flash chip - and survives a power outage perfectly fine.
I’m not finding a cite off-hand, but I’ve read for years that cell phones can be tracked when turned off.
They can certainly be ACCESSED when turned off–
Do some of the older phones not have a mode like the iPhone’s “power down”? The implication being, the power down was designed for the iPhone specifically because the battery is not removable, so something equivalent was needed.
Then again, does the name “airplane mode” actually lie? I can’t imagine the FAA tolerating that.
What md2000 said, I think. If you turn your phone “on” every once in a while and you find that the battery isn’t draining (that’s assuming you don’t keep it plugged into the charger all the time), then I don’t think it can be communicating. As I’ve understood it, generating the radio communication is the major power drain in cell phones.
Not that I’m aware of. Off pretty much means off.
I don’t think the cell radio stays on when a phone is off. But what sort of mechanism turns the phone on? Something must be responding to you pressing the on button, I don’t know if it’s as simple as a relay or some sort of low-level software that runs. Also someone mentioned alarms being able to turn the phone on, so it seems possible that some low-power low-level operations can take place in a phone that’s “off.” However I still don’t think the cell radio could run, that is one of the biggest battery drainers aside from the screen.
I remember during the search for Jessica and Holly that they were trying to use their phones to find them. I think they did something like switch their phones on from a distance, something like that. If you can do that, they can’t be fully switched off, right?
This is all a terminology thing. “Off” is off. AFAIK, all phones can be turned off-- even iPhones. (And no, you don’t need to remove the battery-- typically you hold the power button for about 10 seconds, then a message will appear on the screen saying “swipe down to turn off phone”.) Phones have to be able to power fully off because that’s the only way you can insert/replace a SIM card-- SIM cards can’t be hot-swapped into a device that’s already turned on.
That quote from Huffington Post is confused in two ways: 1) phones that are asleep in almost all cases turn off their GPS circuitry (to save power), and 2) GPS doesn’t send any data, they only receive. So you can’t be tracked via GPS.
If your phone is asleep, which is what it is 99.9% of the time unless you go out of your way to shut it down, if can be tracked because it’s “pinging” the nearest cellphone tower. This is required so the phone network knows what tower to talk to if your phone number has an incoming call or text. On the other hand, this “tracking” is only to the nearest tower-- which could be miles away.
I think a lot of people are confusing “sleep” with “off”.
I’m not convinced. I set an alarm, I power OFF my cell phone. It turns on and the alarm goes off.
If there’s no power flowing to the cell phone chips, how did they know to trigger the alarm?
Battery removed is OFF. Battery in? I have doubts…
What model of phone do you have? And are you sure you turned it off-off and not just sleep-off?
It’s possible there’s a model of phone that can’t be turned off. I’ve never seen one. And I’m skeptical. But who knows.
I definitely remember my Nokia doing that: switch it off, ie hold the off button on the top of the phone down for a long time, and the alarm would still ring. That would’ve been the… 3310? Or something?
Considering the times, it’s quite possible Holly and Jessica had the 3310, or something pretty similar.