24-11-2012, 01:52 PM
Analysis of International Numbers of a Cell Phone
cell phone.ppt (Size: 1.41 MB / Downloads: 46)
Introduction to IMEI no.
The IMEI (International Mobile Equipment Identity) is a unique 15
digit code used to identify an individual mobile station to a GSM or
UMTS network. The IMEI number provides an important function, it
uniquely identifies a specific mobile phone being used on a mobile
network. The IMEI is a useful tool to prevent a stolen handset from accessing a network and being used to place calls. Mobile phone owners who have their phones stolen or lost can contact their mobile network provider and ask them disable a phone using its IMEI number. With an IMEI number, the phone can be blocked from the network quickly and easily. It is important to note that swapping a SIM card will not stop a phone from being banned. IMEI numbers are stored in the phones themselves, not on the SIM cards.
SIM (Subscriber Identification Module)
GSM mobile phones require a small microchip called a Subscriber
Identity Module or SIM card, to function. The SIM card is approximately
the size of a small postage stamp and is usually placed underneath the battery in the rear of the unit. The SIM securely stores the service-subscriber key (IMSI) used to identify a subscriber on mobile telephony devices (such as mobile phones and computers). The SIM card allows users to change phones by simply removing the SIM card from one mobile phone and inserting it into another mobile phone or broadband telephony device. SIM cards are used with carriers that operate on the Global System for Mobile Communication (GSM) network.
Analysis of an IMEI no.
A) Structure of an IMEI Number
IMEI number comes in a 15 digit sequences of numbers. The IMEI format currently utilized is AA-BB-CC-D.
AA: These two digits are for the Reporting Body Identifier, indicating the GSMA approved group that allocated the TAC (Type Allocation Code).
BB: The remainder of the TAC
CC: Serial sequence of the Model
D: Luhn check digit of the entire model or 0 (This is an algorithm that validates the ID number)
Analysis of SIM card
A SIM is held on a removable SIM card, which can be transferred between different mobile devices. SIM cards were first made the same size as a credit card (85.60 mm × 53.98 mm × 0.76 mm). The development of physically smaller mobile devices prompted the development of a smaller SIM card, the mini-SIM card. Mini-SIM cards have the same thickness as full-size cards, but their length and width are reduced to 25 mm × 15 mm. The newest incarnation known as the 3FF or micro-SIM has dimensions of 15 mm × 12 mm. Most cards of the two smaller sizes are supplied as a full-sized card with the smaller card held in place by a few plastic links; it can easily be broken off to be used in a device that uses the smaller SIM.
SIM Security
Information inside the UICC can be protected with a PIN and a PUK.
A PIN locks the SIM card until correct code is entered. Each phone network sets the PIN of SIM to a standard default number (this can be changed via handset). If PIN protection is enabled, the PIN will need to be entered each time phone is switched on. If the PIN is entered incorrectly 3 times in a row, the SIM card will be blocked requiring a PUK from the network/service provider.
A PUK is needed if the PIN is entered incorrectly 3 times and the SIM is blocked (phone is unable to make and receive calls/texts). The PUK can be received from the network provider, or possibly the GSM cell phone manual.
Caution: if PUK is entered 10 times incorrectly, the SIM card is permanently disabled and must be exchanged