If you have ever seen a spy movie, or a kidnapping flick, you would have noticed that the first thing the police does is try and trace the phone number to a geographic location. If you have always wondered how a phone number trace works then this article is designed to help you. The first thing to understand about phone number tracing is that its almost always instantaneous, most movies incorrectly depict that tracing a phone number is a lengthy procedure this is not so. All it takes to trace a phone number to its source is to get in touch with the telephone company the number is registered with.

Landline numbers are the easiest to trace, they can be pinpointed to the exact location where they are installed. All one has to do is use the number displayed on the CID (Caller ID) and run it through a database of phone numbers, and the phone number can be traced to the exact geographic location. There is a common rumour that people hack into the exchange and actually tamper with the routing system to disguise the original phone number; this is probably more myth than truth and the moment any change is made to the telephone system the telephone company knows instantly.

The more difficult devices to trace are mobile phones, since mobiles phone numbers can be acquired using a false name or ID (in case of fixed line phones the name does not matter as the location is fixed). Mobile phones acquired using false IDs may not immediately reveal the identity of the caller, but by using a complex mechanism one can actually pinpoint the location of the mobile phone to a triangulated area. The way a cell phone signal works is what makes tracing a cell phone number possible.

A cell phone number can be traced using the number of signal towers the cell phone is in contact with. Ideally to get a certain trace on a cell phone signal, it requires the cell phone to be in contact with 3 or more signal towers. The moment a cell phone is in contact with 3 cell towers, the phone number can be traced to a triangulated area. Also using the cell phone number it is possible to find the IMEI number of the handset (if the phone was provided by the cell phone company also).

In fact all cell phones that boast of having an in built GPS (Global positioning system) make use of the technology mentioned above, and do not use GPS the traditional way by getting in touch with a satellite. So in essence tracing a cell phone is a simple task, the higher the number of towers that are in range of the cell phone the easier it is to find the exact location of the cell phone. It is therefore easier to trace a cell phone number in large cities as the number of cell phone towers is usually higher in cities and densely populated areas. Like landlines there are popular myths that the cell phone number too can be disguised this is only partly true.