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I have a SIM card alone without cell phone and battery. Can it be be tracked?

Andrei Botalov
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priv8 s0cket
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2 Answers2

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The SIM card must be plugged into a device for it to be functional in any way. It does not contain a power supply or an antenna. As such, it'd be impossible to track a SIM card on its own.

However, once you plug it into a phone and power it on, the IMEI number of the phone and the SIM's serial number will be transmitted to the nearest cell tower(s).

Polynomial
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  • And so its needs 3 towers to locate the cell phone ? – priv8 s0cket Aug 20 '12 at 21:48
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    It doesn't really work like normal signal triangulation. If you've got agents in the field, they can use special equipment to triangulate a phone's signal, but it's not the usual method. If a SIM card is connected to Tower A, you know it's within the range of Tower A's service area. If the announcement was heard by Tower B too, you've got a nice small intersection. If it's within the range of towers A, B and C, that's an even smaller intersection. If it transitions from A to B, you know the direction. The rate of transition will tell you the speed. You just have to guess using what you've got. – Polynomial Aug 20 '12 at 21:51
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    You can further enhance the estimate of the distance to a tower using the strength of the signal. Unfortunately, it's a weak estimator at best, because you don't know what the terrain is like, what weather conditions might be affecting the signal, what the battery charge level is, whether the phone is indoors, whether the phone is underground, etc. – Polynomial Aug 20 '12 at 21:54
  • Wow.. thanks for these info's ! Interresting :D Also i can add that if the cell phone use a jammer or a resistance it should dissapear from the towers, i think but not sure. – priv8 s0cket Aug 20 '12 at 22:02
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    If you use a jammer, those cells stop working and engineers/police may come looking for you. Your phone will also not be working at that point - a jammer is a DOS tactic, not a stealth tactic. – Rory Alsop Aug 21 '12 at 08:28
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    The thing about jammers is that they're just powerful transmitters that drown out other signals. In terms of triangulation, this actually makes it easier to find you, or at least find the jammer. – Polynomial Aug 21 '12 at 08:38
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    You can find someone off a single ping on a tower. Using signal strength maps to view local cell phone coverage, it was determined that there was only a single direction the signal could have come from as the other towers would have picked it up otherwise. It saved the person's life. Not always doable, but detective work, knowing radio paths and your local terrain can pay off immensely. – Fiasco Labs Dec 15 '12 at 05:44
  • @FiascoLabs That is true, though it's an unusual case. Smart, though. – Polynomial Dec 17 '12 at 07:08
  • @Polynomial Yes, usually triangulation is needed, either from fixed stations or by moving the receiving system around and using a directional antenna for most radio signals. Cell phone systems provide other interesting properties like being able to track where signal is missing, a sort of reverse radar effect. – Fiasco Labs Dec 17 '12 at 17:37
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Any SIM/Computer which is not in any network cannot be traced. SIM card are slave computing device which requires an entity to send a command to which it shall respond to. To talk to SIM, SIM is needed to be powered. A typical GSM mobile SIM doesn't support being energized through magnetic induction so it requires power to be transmitted through physical contacts which is typically provided by the mobile device unit.

Another important aspect is that SIM never talks to the GSM Network, SIM is first traced by the Mobile Equipment which request the SIM to provide its IMSI number. The Mobile equipment sends the IMSI number to the network it is trying to hook into. If the SIM is blocked like multiple wrong pins, than SIM might not allow the device to read the IMSI as well. It depends on how the OS in SIM is programmed.

Hence a SIM card cannot be traced unless it is inserted into a mobile handset and the handset is in cellular provider coverage area. And yes the mobile battery should have sufficient charge.

Mohit Sethi
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