Prepaid Wireless (aka Tracfones)

[Edsel]

In my DC game one of the things that is popular among the characters is the use of Tracfones grant a higher degree of security. The thinking here is that since you can buy the phones and cards with cash it makes it harder to trace back a phone to an individual.

 

I'll admit I know little about these devices. I haven't ever even used a prepaid phone card. Is our logic correct on the benefits of Tracfones or have we invented a mesure of anonymity that isn't really there?

[ghost-angel]

Re: Prepaid Wireless (aka Tracfones)

 

Yes and No. The phone itself can be traced and located normally (triangulation from last point of broadcast).

 

Finding who owns the phone requires finding out who it was issued to. And unless the store takes down someone's info (name, addresses, credit card, et cetera) you're not likely to know who owns the phone.

 

If they pay cash in a 7-11 and no info is taken on the phone or calling card than after the fact tracing on the phone is impossible. Tracing the phone while it's being used is possible.

 

To do that I would find a person they contact regularly, or at least a number they call, and tap that line. When it's being used they then find the originating calling number (the Tracfone Cell), triangulate and locate, then send someone out to get the caller if possible.

 

Otherwise it's pretty anonymous as to who used the phone - doubly so if it's destroyed afterwards.

[Ternaugh]

Re: Prepaid Wireless (aka Tracfones)

 

Depends on the individual phone, the service, and behaviors of the user.

 

Prepaid services use a supporting network (or, from what I can find about Tracfone, several networks) to provide coverage. While a cellphone is on, and within a service zone, it is being actively tracked by the system, so that incoming calls may be sent to it. Newer handsets are required to have certain features that allow 911 calls to be located more precisely, but even older handsets can be found with a triangulation method using the signal from multiple towers and software already in use by the carriers.

 

That tracking is achieved by giving each phone a unique electronic serial number (ESN), which is usually recorded when a phone is sold. This is so that the dealer can get a bonus payment upon activation. So, whenever a prepaid enters service, the virtual carrier (in this case, Tracfone) would know exactly what dealer sold it and where it was sold. Prepaid air cards for most services are also tracked in a similar manner, since the actual cards require activation at point-of-sale. And since these devices are usuallly sold in convenience stores and electronics sections, there are usually multiple cameras on the purchaser, recording the transaction. There have been cases where this linkage has been used in a prosecution.

 

Note that the phone networks that we are assuming here are those found in the US. For prepaid service, these tend to be CDMA networks (Sprint and Verizon). Prepaids in other parts of the world, however, tend to be based upon GSM designs (T Mobile and Cingular in the US, and just about everyone else in the world). GSM uses two things to identify a phone: the ESN and the id of the GSM chip, which is removable and transferable to another handset. And in many parts of the world, buying prepaid airtime means buying a GSM chip with a number of minutes on it.

 

Now, this is where certain members of Al Queda made a mistake several years ago. One of their agents bought a load of GSM phones and prepaid chips for use by their operatives. Due to a misunderstanding about the way that prepaid GSM works, it was common for the operatives to throw out the phone after a certain period of time, but they would transfer the chip to the new phone. This meant, effectively, that those under surveilance did not "anonomize" themselves, because the network ID of the phone effectively remained the same. Investigators did note the change in ESN, however. And that big buy meant that they knew what block of chips were in use.

 

As a further note, I use Virgin Mobile as my prepaid service. It required me to register the phone, and to provide information about me (although I guess this could have been faked). Some other prepaids actually require more information (Verizon and T Mobile did, when we would sign people up for the services). Tracfone didn't when we used to sell it, but it could upon registration.

 

So, if they're careful, and don't draw undue attention to themselves, they're probably ok. But if some investigator figures out that the same handsets are in use at several events, well, they might just find out that they weren't as anonymous as they thought.

 

JoeG

[ghost-angel]

Re: Prepaid Wireless (aka Tracfones)

 

Another techincal note is a cell phone (or any cellular device) is connected to 2-5 cellular towers at any given moment to provide the best signal strength and fastest response time.

 

the towers report to the Telephone Switches which ESN or GSM they are currently talking to so the network knows where to route a transmission.

 

You need 3 towers to accurately pinpoint the location of a cell phone, but if you're just tracing the path the phone is traveling on you just draw a line and guesstimate based on which towers report having communicated with the phone at any given moment.

 

The trick is Telco's don't keep records of passive communication (no active transmission, just the tower-phone connection), but they do for active communication (for billing purposes, amongst other things) with a phone (from which number to which number, where the phones were located, which towers they were using).

 

So you've got two options to "track" a prepaid phone user with no user, or bad user, information on record:

After the fact tracing.

Active tracing while you're watching, best started when a call is made it's then easy to just follow the signal around.

[Edsel]

Re: Prepaid Wireless (aka Tracfones)

 

The characters are pretty security conscious. They buy the phones at busy retail outlets and pay cash only. They buy short duration cards, keep their calls brief and never use them while at home or a location they want to keep secret. They destroy the phones and buy new ones (from different sellers) frequently, and never use the same card for more than one call (they have the wealth to cover these costs).

 

Eventually they'll probably invest the character points needed to obtain radios with scramblers or something similar.

 

I really ought to write-up these tracfones as a piece of equipment so that they have to use up some of their equipment allowance to carry one around, they are just too useful to let them get away with it for free.

 

BTW thanks for the Info. Rep to Ternaugh and rep to ghost-angel when the system will let me rep you again.

[Threnody]

Re: Prepaid Wireless (aka Tracfones)

 

Howdy!

 

It's worse than y'all think. If the battery is in the cell phone it can be located, cause the phone is given off a signal all the time---a signal to locate you.

 

It has to, otherwise nobody could call you. So your phone can be found any minute any day.

 

Unless --- you have a pager and leave it running whilst you take the battery out of your cell. That way, someone wants to talk to you, they call your pager number. Your pager tells you who wants to call and if you want to talk to them you put the battery in your cell and go.

 

Important! Pagers really are passive. They don't give off no signal; OK, some fancy-pants models do cause they got "special additional features," but the plain ol' ones don't.

 

Course you can be located while you're talking on the cell, but if you're careful that's not a biggie.

[ghost-angel]

Re: Prepaid Wireless (aka Tracfones)

 

Howdy!

 

It's worse than y'all think. If the battery is in the cell phone it can be located, cause the phone is given off a signal all the time---a signal to locate you.

 

It has to, otherwise nobody could call you. So your phone can be found any minute any day.

 

Unless --- you have a pager and leave it running whilst you take the battery out of your cell. That way, someone wants to talk to you, they call your pager number. Your pager tells you who wants to call and if you want to talk to them you put the battery in your cell and go.

 

Important! Pagers really are passive. They don't give off no signal; OK, some fancy-pants models do cause they got "special additional features," but the plain ol' ones don't.

 

Course you can be located while you're talking on the cell, but if you're careful that's not a biggie.

We've already covered the Cell phones being tracked - they have to remain connected to the cellular network. But that is a passive signal and not stored so you have to be actively looking for it - and know which ESN to look for.

 

As for pagers - most pagers do remain connected to the cellular network these days for fast pager delivery in the same way a cell phone does. It shoots it's own ESN to local towers so when a page is sent out it takes less time to track down the pager and send the page - otherwise the Telco's spend time and money having a bunch of towers ping out looking for the ACK from the pager in question delaying the page as the whole city looks for a "off the network" pager that isn't transmitting passively.

 

In fact - I can't think of a single modern pager that doesn't connect to a tower passively.

[Lemurion]

Re: Prepaid Wireless (aka Tracfones)

 

Actually, the phone isn't transmitting all the time. The battery life wouldn't let it. What happens is when your phone powers on it sends out a signal to the network with its IMEI (GSM equivalent of an ESN) and the ICCID of the SIM card. It then goes through authentication and registers on the network. Once that is done it stops transmitting.

 

The tower will then keep this device in its record for a certain length of time, before automatically de-registering it. Every time it is turned back on, it re-registers based on the location it's currently in.

 

The way a cell phone receives a call is exactly like a pager. The tower sends out a broadcast signal paging that phone. Once the phone picks up that signal, it starts to ring. Then when you hit the send button to answer the phone, it calls the tower, which then connects the two calls (your phone's outbound call to the tower and the other party's inbound call to your phone). There you have a connection.

 

However, the phone is only actively connected to the towers when it is actively involved in a call or other specific data transmission. The rest of the time it's sitting passively.

 

Also, most people at the telcos do not have access to real-time billing information, and even those that do rarely if ever have the information to answer location questions. In my day job I have direct access to two low level telco billing systems (the one that does record the tower) and it only indicates the one tower that is handling the call, you can tell approximate location, but not triangulate.

 

Triangulating a cellphone can be done, but it's not easy, and you aren't going to be able to just contact the telco and get the records like that.

[Edsel]

Re: Prepaid Wireless (aka Tracfones)

 

Okay, so I am guessing that when, on a show (like 24), they tell people to take the battery out of the phone so that they won't be located by the super-duper electronic surveilance network, it's just fiction? Unless you are actively using the phone they are not going to be able to locate you based upon some passive signal it emits?

[Threnody]

Re: Prepaid Wireless (aka Tracfones)

 

Y'know, Lemurion, I didn't say a cell transmits continuously, just repeatedly.

 

ghost-angel, pagers without all that fancy-pants "fast page" BS and so on can be bought. You just gotta be persistant.

 

I sat me down once with a guy what knows his electronics, and he put a cell in a wire cage and hooked up an ossiliscope. I SAW the spikes as it blipped it's "here I is" message over and over. I saw the pager NOT send out no such message.

 

I ain't talking theoretical, I SEEN it. A cell transmits a signal, repeatedly but not constant, that it can be found with.

 

And I ain't talking how the cellphone network is supposed to handle that signal, I'm talking about what can be done about finding it by someone with high-tech equipment, or access to the network's equipment (from cracking or from having the gummint behind you).

 

No Edsel, it ain't fiction. You got a cell in your pocket, you CAN be found unless you took out the battery. Simple fact.

[KA.]

Re: Prepaid Wireless (aka Tracfones)

 

I think that if you were going to do something in a fictional world, you might want to consider cloning someone else's phone.

All I know about this topic is what I learned from a Spiderman novel, so bear with me.

All the information about "I am the phone with this ID, I am registered to Person X, I connect with Network Y" can be stored on a chip, and is sent out when the phone is used to make a call.

At one time, you could scan for that information when a phone was nearby (I think it is encrypted now, but if we are talking about a fictional super-genius, that shouldn't be any problem).

If you could successfully clone the phone of an innocent bystander, and then use that signature for your phone, it seems like it would be very hard to 'casually' track you.

Assuming that the person with the phone you cloned is a Cab Driver, or UPS Driver, or Bike Messenger, or Pizza Delivery Dude, and you are moving around quite a bit too, it would be pretty hard to keep track of who was who and who was where.

If you did this on a daily basis, swapping out phones all the time, you would probably be fairly secure.

 

KA.

[ghost-angel]

Re: Prepaid Wireless (aka Tracfones)

 

Cell Phones, and most Pagers, ping the towers every so often (1-5 minutes typically) to let the network know their position (incidentally, this is how a Cell Phone guages it's Signal Strength constantly). Pagers will ping as infrequently as once an hour, sometimes even less frequently than that - but they do ping the network, especially text pagers. Some of them, usually ones carried by the technician I need to get a hold of is set to ping the towers about once every 24-48 hours and receive the pages about 24 hours after that.....

 

The only way to stop triangulation of a cell phone (active call or not) is to turn it off. You don't have to remove the battery, but that's one of way of getting it to stop transmitting. End result is it has to be powerless.

 

I work with telephone equipment and companies all day - it's my job. I actualy work with all sorts of telecommunications equipment: Cellular, Radio, Satelite, POTS/TOLL, Circuits and other proprietary comm methods over telco networks.

[Steve Long]

Re: Prepaid Wireless (aka Tracfones)

 

Hee, hee -- this is good TUS stuff. Thanx, guys! Some of you may be pestered with more questions at a later date.

[Edsel]

Re: Prepaid Wireless (aka Tracfones)

 

Okay so the latest verdict seems to be...

 

If you want to prevent your cell phone from being traced you have to power it down. Removing the battery isn't really necessary but turning it off is definately required. I'd also think that the normal police department is not going to normally go to the trouble required to triangulate on a non-active (but still turned on) cell phone. They could do it if they really wanted to go to but they'd need a compelling reason to go to that extreme.

 

This has been a very enlightning thread and thanks to all who have participated.

[Zeropoint]

Re: Prepaid Wireless (aka Tracfones)

 

I looked at this subject line and read:

 

Re: Prepaid Wireless (aka Takofones)

[Edsel]

Re: Prepaid Wireless (aka Tracfones)

 

I looked at this subject line and read:

 

Re: Prepaid Wireless (aka Takofones)

I tried that... All I got was a dead line.

[ghost-angel]

Re: Prepaid Wireless (aka Tracfones)

 

Hee' date=' hee -- this is good TUS stuff. Thanx, guys! Some of you may be pestered with more questions at a later date. [/quote']

Feel free to pester me with any Telephony Network related questions you might have...

[Steve Long]

Re: Prepaid Wireless (aka Tracfones)

 

Prepaid Wireless (aka Takofones)

 

Well, he definitely doesn't need any wires....

[ghost-angel]

Re: Prepaid Wireless (aka Tracfones)

 

Takofanes' influence would certainly explain some wireless network policies....

[Oneway]

Re: Prepaid Wireless (aka Tracfones)

 

As Ghost said (or at least eluded to) use it once.

 

After all, $50-100 per call, is a small price to pay for security.

 

Remember, contrary to popular belief, Life is expensive.

Death, on the other hand, can be hand for next to nothing.

[CBikle]

Re: Prepaid Wireless (aka Tracfones)

 

On a related question:

 

Can disposable phones make international calls (lets say U.S. to somewhere in Europe), and if so, how hard are they to track from the U.S. ?

[ghost-angel]

Re: Prepaid Wireless (aka Tracfones)

 

On a related question:

 

Can disposable phones make international calls (lets say U.S. to somewhere in Europe), and if so, how hard are they to track from the U.S. ?

If they are prepaid generally they can make calls anywhere. If you are using a Calling Card (which is common) then they can make interantional calls.

 

International Calls are no harder to track than Domestic Calls. As long as it hits the Domestic Telco Network it can be tracked.

[Lucius]

Re: Prepaid Wireless (aka Tracfones)

 

Takofanes' influence would certainly explain some wireless network policies....

 

Oh? how?

 

Lucius Alexander

 

The palindromedary ponders the pronunciations of "Takofanes" and "Telephony."

[ghost-angel]

Re: Prepaid Wireless (aka Tracfones)

 

Oh? how?

 

Lucius Alexander

 

The palindromedary ponders the pronunciations of "Takofanes" and "Telephony."

Both are soul sucking evils bent on dominating the world....

[Ternaugh]

Re: Prepaid Wireless (aka Tracfones)

 

Both are soul sucking evils bent on dominating the world....

Yes...but only one is Bluetooth compatible!

 

JoeG