What does Satan need with a cellphone ?
I worked for a major phone provider briefly, and they had a service you could buy that would allow you to track one of your cell phones to within a small geographical area (it was something like a quarter-mile radius, IIRC).
Oh, Satan doesn’t have the cell phone. The main character’s cousin finds her through GPS on their cell phones, which is why I had to find out if it sounded even halfway plausible. Satan turns up AFTER the cell phone incident, complaining about the available espresso and offering to make a deal in exchange for any extra souls that you happen to have lying around. Thanks, Seanette! 
I have to admit, Cornholers just sounds like an unfortunate name at this point. But I’m sure it wasn’t when it was first adopted.
I know the police can use triangulation to track a cellphone (with the consent of the service provider), but can they also use GPS if said phone doesn’t have a tracking program like “Find my iPhone” active? Looking at my iPhone, it only powers up the GPS antenna when an app requires it - the “location services” arrow appears on the display when it is active. Can this be fired up remotely on demand by the service provider to get an accurate fix?
Yes, GPS can be remotely activated by the operator, primarily for e911. Tracking phones via GPS without a warrant is currently a gray area (no supreme court case yet), but it IS done without a warrant in many jurisdictions.
That would be phone and carrier dependent, I believe. I think the first phone I worked on that had GPS didn’t have this capability - I remember lots of discussion over whether to include it. But that was many years ago.
Different countries have different privacy laws, which could come into play.
-D/a
So to summarize:
Th authorities have access to internal technical details and can track you using cell tower triangulation, and if the phone has it (most smart phones do) augmented by GPS.
There are apps that can report your phone position to your PC. It’s not unheard of for parents, a jealous boyfriend, stalker, whatever to stick one of these on a phone surreptitiously if they have access. I’m sure you’ve seen the stories of people who recovered their phone or macbook when they got a location/IP address from it, or took a photo of the theif from the built in camera. All techincally possible, if the program is installed.
It is remotely possible (especially for Android, less secure) that some exploit can install this function simply by having you browse to a web site, open an infected email, etc. Basically, pick up a trapdoor program just like a PC might. Very much less likely, but as the phones get more complex, more likely.
Old analog cell phones used to simply broadcast audio over assorted channels; conveniently preceding each transmission with a shot burst identifying the phone. That’s how the News of The World and similar “journalists” could verify that the recording of Charles and Camilla discussing his desire to be her soiled panties were genuine. Today’s cellphones use encrypted digital technology and such interceptions are typically beyond the ken of mortal men who do not work for the NSA. Plus, to simplify the function of cell towers, digital cellphones adjust their transmission volume to ensure the tower hears all transmissions at the same volume. (Which is why your battery drains faster in areas of bad reception). The digital transimssion is in packets, and multiple packets from multiple phones can use the same channel (interwoven) or phones can be told by the tower to hop frequencies to balance the load. It is no longer as simple as recording 28 channels in strategic places.
years ago, trunk lines between land stations were often routed by microwave tower; these consisted of standard telephone packet connections. A fellow who was “retired” from the CSE (Canadian NSA equivalent) due to a drinking problem, wrote a book on the tech they used around 1990. Some friendly fellows from a Washington suburb lent these guys some interesting toys - point it at a standard microwave relay tower, it would separate and capture all the telephone conversations going by.
Of course, nowadays much of the traffic - regional or long distance - is likely sent on fiber optic. Unless you can gain access to the wiring closests and codes of the top telephone relay sites in the USA (and later get retroactive immunity from illegal spying charges) you are not likely to intercept many conversation, and specifically not the one you want.
The weakest link for landlines is typically the final, analog mile - but that’s highly illegal nowadays and in many cases (VoIP, SKYPE, fiber feed, etc.) becoming technically challenging.
The authorities, however, have been mandating new technology has the ability to locate, for 911, law enforcement, and other reasons. There are frequent suggestions that anyone providing phone services must allow authorities the technology to wiretap it (with a warrant).
I should add another “unintended consequence” - if you take a photo and update it to somewhere like facebook in realtime, it may embed the GPS info in the JPG tags; so that someone downloading the picture of the cute kitty in the store window can say “oh, this was on 189 W 34th street at 1:39 today - 5 minutes ago”. My iPhone is perpetually asking if I will allow use of location info for this or that. My latest point-and-shoot camera has GPS capability too - a sure battery-killer.
Very nice summary, md2000.
FYI, in the US, E911 is required, but I believe it’s allowable to implement it without GPS. I’m not familiar with the technical details.
-D/a
Wow, what a great summary! So… do you agree that two people could use this kind of technology to track each other with permission from both? In this case, it’s two cousins.
Well, if you want to ramp up the whole “social network” concept up to 11 you could have someone send out facebook feeds asking “have you seen this guy?”. Now if something like facebook allowed you to target this question to a reasonably small area that seems plausible.
Don’t use fancy technology. Use fancy technology to make the minions your snitches.
Ha! No, I don’t think I want it to get that elaborate. 
The point of the GPS technology is that the main character’s cousin found her and then lost her, which shouldn’t have happened. But when you briefly travel to another dimension inhabited by devils, demons, and assorted things that go bump in the night, that often occurs.
With permission? Absolutely.
-D/a
That’s how John Mcafee got caught.
http://www.wired.com/gadgetlab/2012/12/how-vice-got-john-mcafee-caught/
There have been times when I have called my insurance agency for roadside and the automatic message was able to locate me from my cell phone GPS.
Apparently many criminals realize this now and will remove the battery from a cell phone so as not to be tracked since it continues to locate near towers even when it is simply turned off. My question is what about when the cell phone is automatically shut down when power gets so low it can no longer operate. Does it continue to find proximal towers or is it as effectively shut down as if the battery had been removed?
(This question was meant to stay within the confines of the current discussion and not be a hijack. If it deviates off subject please disregard.)
He’s not the only one. Dateline last week had the story of the Ponte Vedre kidnap victim that turned out to have been behind a fake extortion plot and the GPS extracted from a cellphone pic was an integral part of the break in the case.
That’s kind of an interesting question, actually. When Victoria (main character) is lost, and her cousin Caleb can’t find her through her cell phone, that could be one of the theories they come up with-- that the power went too low and it was automatically shut down.
When the battery drops below a critical voltage level, the phone shuts down. It might maintain a (relatively) slow clock..but it does not do any RF. So it isn’t tracking cell towers, and isn’t talking to them. For the purpose of this discussion, if the battery gets low enough, the phone is dead until it is recharged.
-D/a
Based on my experiences with using Google Latitude in a suburban area:
- it usually thinks I am across the street, and one house over as well
- from time to time, for a couple minutes, it thinks I’m about two miles away, then it thinks I’m back home
At one point during a highway drive, it pegged me as being quite far from my real location: a solid 10 miles off.
But it fixed that in a couple minutes.
Let’s distinguish between “turned off” as in I hit that button on top of my iPhone and the screen goes black; but I will still receive a phone call - versus hold the button until it says “slide to power off” and it ceases to be electronically active. Theoretically airplane mode will do the same thing - no broadcasting. If you don’t know the model of phone and what each mode is, removing the battery is most effective - especially on an iPhone 
Whil the phone is still alive, even if the screen is black, it sends a “Hello” ping to the cell towers every second or so, to ensure there are still bars, and so the cell system knows which tower it’s close to and if the phone is online to take calls. So theoretically an interested party could track your wanderings minute-by-minute every waking minute.
Just like instant-on TVs and wake-to-record VHS and DVRs, the line between “ON” and “OFF” is pretty blurry nowadays.
I think Verizon is the best network to use if you want to track cellphones from one dimension to the next… or is it ATT where the phone calls seem to disappear into a different dimension. I’m sure there’s a story in the fact that a lot of email spam appears out of nowhere from a different dimension.