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#1
Old 06-10-2013, 09:10 AM
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Cell Phone Tracking when off.

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?
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#2
Old 06-10-2013, 10:22 AM
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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.
#3
Old 06-10-2013, 10:24 AM
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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?
#4
Old 06-10-2013, 10:37 AM
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Here is one such article.
Quote:
Originally Posted by Huffington Post
Cell phones keep sending a signal several times a minute even though they are turned off. The only way to stop the GPS signal from a cell phone is to take out the battery, which is nearly impossible for the 75 million consumers who own an iPhone.
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.
#5
Old 06-10-2013, 10:54 AM
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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.
#6
Old 06-10-2013, 10:59 AM
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I know that they can tell what your location was just before you turned it off.
#7
Old 06-10-2013, 11:00 AM
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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.

Last edited by md2000; 06-10-2013 at 11:03 AM.
#8
Old 06-10-2013, 11:06 AM
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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.
#9
Old 06-10-2013, 11:17 AM
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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.

Last edited by Cartooniverse; 06-10-2013 at 11:18 AM.
#10
Old 06-10-2013, 11:39 AM
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Quote:
Originally Posted by Cartooniverse View Post
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.
#11
Old 06-10-2013, 12:55 PM
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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--
Quote:
The FBI appears to have begun using a novel form of electronic surveillance in criminal investigations: remotely activating a mobile phone's microphone and using it to eavesdrop on nearby conversations. . . .
Kaplan's opinion said that the eavesdropping technique "functioned whether the phone was powered on or off." Some handsets can't be fully powered down without removing the battery; for instance, some Nokia models will wake up when turned off if an alarm is set.
http://news.cnet.com/2100-1029-6140191.html
#12
Old 06-10-2013, 01:17 PM
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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.

Last edited by md2000; 06-10-2013 at 01:18 PM.
#13
Old 06-10-2013, 01:34 PM
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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.

Quote:
Originally Posted by md2000 View Post
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.
#14
Old 06-10-2013, 02:46 PM
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Quote:
Originally Posted by md2000 View Post
Do some of the older phones not have a mode like the iPhone's "power down"?
Not that I'm aware of. Off pretty much means off.
#15
Old 06-10-2013, 03:12 PM
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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.
#16
Old 06-10-2013, 03:36 PM
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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?
#17
Old 06-10-2013, 04:28 PM
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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".
#18
Old 06-10-2013, 04:32 PM
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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.....
#19
Old 06-10-2013, 04:34 PM
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Quote:
Originally Posted by Cartooniverse View Post
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.
#20
Old 06-10-2013, 05:17 PM
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Quote:
Originally Posted by Blakeyrat View Post
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.

Last edited by gracer; 06-10-2013 at 05:17 PM.
#21
Old 06-10-2013, 05:59 PM
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From the Nokia 3310 manual, Alarm section:

Quote:
When the reminder time is reached

If the phone is switched on, it sounds an alarm and flashes its lights and the
reminder text. You can stop the alarm by pressing . If you press (Snooze),
the alarm stops for a few minutes.

If the phone is switched off, the reminder is displayed when you switch on the
phone again.
#22
Old 06-10-2013, 07:19 PM
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Quote:
Originally Posted by Blakeyrat View Post
From the Nokia 3310 manual, Alarm section:
Haha, oh well, at least I am not alone in my delusion! I remember the alarm going off, and then still having to switch it on and put in the code and everything. The reason I remember is that I was surprised when a later phone did not do this.

But it must just be the crazed ramblings from a brain confused over these past 13 years...
#23
Old 06-10-2013, 07:45 PM
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Quote:
Originally Posted by Cartooniverse View Post
I'm not convinced. I set an alarm, I power OFF my cell phone. It turns on and the alarm goes off.
I agree that your phone is probably asleep, not actually turned off. But let us know the model and we can verify.
#24
Old 06-10-2013, 07:53 PM
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Hmmmm. I am now feeling very insecure about my assertion.

Motorola Droid X 2 On Verizon.

It is not just Hollywood fiction that a cell phone that is asleep pings the towers and can be triangulated. Three towers several miles apart, and you will find someone.
#25
Old 06-10-2013, 07:55 PM
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I've designed and written software for cell phones for over a decade. Lots of misunderstandings in this thread - let me try to clear up a few things.

When a cell phone is powered down..as close to off as it gets with a battery inserted..it doesn't talk to the network. It's can't be remotely activated. It can't be tracked.

The phone is typically in an extremely low power state, with a few different means to bring it up. One of those is the power button. Another is an internal clock (just barely sipping current from the battery) signalling an alarm - this is how the alarm clock feature works. A third is a charger being attached.
Since the phone isn't talking to (or listening to) a network, it can't be remotely turned on by the network. It also isn't listening to GPS, so it can't remember where it is and transmit the information later.

Now, a phone could effectively be faking it by looking like it's off, but still doing talking on the network. As noted above, you'd notice the battery drain.


One minor exception to all this is a phone that supports certain types of NFC. NFC can function without an external power source..but not in any way to usefully track the general public.


Also, there was a note above that SIM cards can't be hot swapped. There's no technical reason you can't do this. I'm not familiar with every model on the market, but I suspect there are some that allow it now.

I'll be happy to go into more detail if anyone has more questions.
#26
Old 06-10-2013, 07:59 PM
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I love it. Nothing like getting the straight dope !! Thank you for the answer.
#27
Old 06-10-2013, 11:39 PM
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Quote:
Originally Posted by Flyer View Post
I'm not finding a cite off-hand, but I've read for years that cell phones can be tracked when turned off.

http://news.cnet.com/2100-1029-6140191.html
The key part of this article is here:
Quote:
An article in the Financial Times last year said mobile providers can "remotely install a piece of software on to any handset, without the owner's knowledge, which will activate the microphone even when its owner is not making a call."
Which also fits along with what Digital is saying:

Quote:
Originally Posted by Digital is the new Analog View Post
Now, a phone could effectively be faking it by looking like it's off, but still doing talking on the network. As noted above, you'd notice the battery drain.
I think this makes sense, that a custom app could be installed which will make the user believe that the phone is completely powered down, when it's not.
#28
Old 06-11-2013, 10:02 AM
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It's my understanding, courtesy of a "good" leak to the NYTimes--which of course may have false information--that the American-Israeli Stuxnet campaign against Iran (or a different simultaneous program whose name I can't remember) turned on the video and recording devices of who knows how many devices, including all Bluetooth ones, so other device and mobile communications were also tapped.

Just mentioning.
#29
Old 06-12-2013, 05:29 AM
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Just another reason to leave the thing at home.

As for battery drain- it might be small.
You might or might not notice, it could be close to zero depending on usage.
#30
Old 06-12-2013, 06:56 AM
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If you really want to be sure, wrap it in aluminum foil after turning it off.
#31
Old 06-12-2013, 08:32 AM
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Quote:
Originally Posted by Cartooniverse View Post
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.....
If you want to test this, set the alarm, then remove the battery. I'll bet that the alarm won't go off anymore. That will prove that "off" is really "standby".

Quote:
Originally Posted by ZenBeam View Post
If you really want to be sure, wrap it in aluminum foil after turning it off.
No, wrap your brain with foil. That's the only sure way to avoid being tracked by the Martians. Little devils, they is.
#32
Old 06-12-2013, 08:54 AM
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Quote:
Originally Posted by Musicat View Post
If you want to test this, set the alarm, then remove the battery. I'll bet that the alarm won't go off anymore. That will prove that "off" is really "standby".
As mentioned upthread, alarms can be set to wake up the device triggered off the clock. You can consider that standby, but I don't think it really is.
#33
Old 06-12-2013, 11:29 AM
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Originally Posted by Musicat View Post
No, wrap your brain with foil. That's the only sure way to avoid being tracked by the Martians. Little devils, they is.
That won't help if they're tracking your cell phone, now will it?
#34
Old 06-12-2013, 02:25 PM
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Originally Posted by Telemark View Post
As mentioned upthread, alarms can be set to wake up the device triggered off the clock. You can consider that standby, but I don't think it really is.
Tell me how the device will wake up with no power.
#35
Old 06-12-2013, 02:32 PM
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Quote:
Originally Posted by Musicat View Post
Tell me how the device will wake up with no power.
The alarm circuitry is extremely low power (think about how little power a digital watch takes). It can be running all the time, while everything else is off (including the radio transmitter and receiver).
#36
Old 06-12-2013, 02:39 PM
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Quote:
Originally Posted by Musicat View Post
Tell me how the device will wake up with no power.
Remove the battery, and it won't wake up. But the fact that the device is triggered by a timer (which granted, is drawing some power but it's low level) doesn't mean it's in standby mode in any meaningful manner. It's not connecting to cell towers or broadcasting anything unless someone has hacked the phone.
#37
Old 06-12-2013, 09:01 PM
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Quote:
Originally Posted by Telemark View Post
Remove the battery, and it won't wake up. But the fact that the device is triggered by a timer (which granted, is drawing some power but it's low level) doesn't mean it's in standby mode in any meaningful manner. It's not connecting to cell towers or broadcasting anything unless someone has hacked the phone.
I guess we need to define "standby." To me, it implies a partially powered unit, able to perform minimal functions and wake up fully when necessary. Whether or not standby mode includes pinging towers, calculating locations or playing tiddlywinks depends on the design, and if you want to call it "sleep" or "hibernate" mode, it's fine with me.
#38
Old 06-13-2013, 10:47 AM
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Quote:
Originally Posted by md2000 View Post
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.
I believe "Carrier IQ", spyware frequently installed by vendors on Android devices, was found to be violating Airplane Mode.

The FBI have been using "Roving bugs" for years. A phone that seems to be turned off is remotely activated in such a way that it seems to still be turned off and the microphone is used to spy.
#39
Old 06-13-2013, 04:08 PM
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From a simplistic perspective..you have a hardware standby mode, and a software standby mode.
In hardware standby, all you have is a very few circuits being powered, including a low resolution clock. The clock can allow a simple timer to run. When the time elapses, it triggers a wake up for the whole system, which then comes up and notifies the user.

In software standby, you can wake up and go to sleep as needed..you can stay camped on a network if you want, although it will take noticeable battery life. If you go into airplane mode and let your display timeout, you are in a low power software standby. If you press the power key until it shows the device turned off, you are in hardware standby.


*All of this is architecture dependent. And not quite true. But it's close enough for this discussion.
#40
Old 06-24-2013, 07:11 PM
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There are no rules

You have to remember that phone are sophisticated HARDWARE + customization SOFTWARE. It can be programmed to do just about anything. Sending a signal is native to the device.
It's like thinking that your webcam is not watching you because the LED light is off. Well surprise - it can easily be kept off while the webcam works. Or come on with a certain cue (think Xbox one). The software needed to reprogram you phone to turn it's 'OFF mode' into a 'listen and track' or a 'wake to 'fake off' on signal' or 'ping check in every 10 minutes' is not that difficult to use. The low resolution timer would serve nicely. A phone who's battery CANNOT be taken out? It's almost to much to resist.
Does you cell phone transmit data when it is off? It does if it is programmed to do so. It does if the NSA wants it to.
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