The Great Indian Tech Blog
Chinese phones with same IMEI numbers are risky
Author: Gadget Techie, Category: Legal, Mobile Phones, Windows Mobile
So all of you with your Hiphones, Ciphones and other Chinese clones with ofcourse be happy with the great and more importantly cheap phones you have. Some Chinese phones even come preloaded with Windows Mobile professional editions 6.1 and 6.0. They have learnt how to pirate even Microsoft’s other mobile applications and libraries, but what they cant do is give you a genuine IMEI code.
The International Mobile Equipment Identity or IMEI code is a unique code that every GSM and UMTS phone must have. The last digit of IMEI is a check digit :
The Check Digit is calculated according to Luhn formula (ISO/IEC 7812). See GSM 02.16 / 3GPP 22.016. The Check Digit shall not be transmitted to the network. The Check Digit is a function of all other digits in the IMEI. The Software Version Number (SVN) of a mobile is not included in the calculation. The purpose of the Check Digit is to help guard against the possibility of incorrect entries to the CEIR and EIR equipment. The presentation of Check Digit (CD) both electronically and in printed form on the label and packaging is very important. Logistics (using bar-code reader) and EIR/CEIR administration cannot use the CD unless it is printed outside of the packaging, and on the ME IMEI/Type Accreditation label. The check digit shall always be transmitted to the network as "0".
The check digit is validated in three steps:
- Starting from the right, double a digit every 2 digits (e.g. 7 → 14)
- Sum the digits (e.g. 14 → 1 + 4)
- Check if the sum is divisible by 10
Now i must say i didnt come up with the following explanations, we came up with them while discussion on forums. How do Chinese generic phones and clones get IMEI codes ?
1. The manufacturer destroys and old phone and allots its number to new phone (highly unlikely)
2. The manufacturer uses the IMEI of stolen phones.
In both the cases it is not hard to see that the manufacturer will not be able to meet the IMEI demand by himself. Hence many Chinese generic phone makers have starting putting the same IMEI in thousands of phones, as a result a lot of people are facing problems.
Some networks ban the usage of the same IMEI by more than 2 phone, this may be banned on a first come first served basis or a straightforward ban all with same IMEI basis.
Another potential threat is the terrorist threat, law enforcement has often used the IMEI as a tool to trace locations of criminals and terrorists. This evidence is very important in terms of reconstructing events. Its not easy to pinpoint location using IMEI but you can get the area and tower the cell-phone is contacting.
The last and third problem is ignorance and theft, in that order. Supposedly i am a gullible customer. I buy the phone w/o realising that its IMEI may be the same as all the other phones by the company. Now my phone is picked from my pocket. I go to the police, being an influential person i am able to tell the operators to ban my phone. Operators will ban phones based on IMEI supplied. and in turn all Chinese phones by that manufacturer will be bricked and become useless for all.
