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What is Sim-Lock. Removing simlock

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This article explains the concept of SIM-LOCK, its main use and the consequences of its removal.

What is SIM-LOCK?

Sim-lock, SP-lock, coding - all these words have similar meaning: a programmed limit in the phone to work with a single network. A sim lock allows a network provider to prevent handsets from being used on other GSM networks. Usually those handsets are sold with a discount, and the provider covers the price difference. The handset stays inside the same network and within a year pays back the expenses of the service provider.

SIM-LOCK could be installed by the manufacturing or distributing company. The network provider orders some quantity of handsets from manufacturer. The producing company supplies the phones along with the SIM-LOCK removing codes. The physical sense of Sim-lock: there is a unique MCC/NCC code of the country and network saved in the SIM-Card. Phone detects those codes when it's powered on. If they have coincided, the telephone works normally, other ways on display appears the following massage: Invalid SIM or Enter the SIM-Lock code. There are some other methods of coding the handsets, but the considered above is the most widespread.

How to remove the SIM-LOCK?

Some European GSM networks allow their costumers to remove sim loks after they have used their services for more than a year. This could be done at a service centre by entering a special code from the keypad (usually it's 8-15 digits).

One can also remove sim lock outside official service centers. The info about lock is saved in the phone's memory. It could be removed by knowing where it saved. A special cable needs to be attached to the handset. Program sends unlocking signal to the phone. Some handsets require more difficult procedure. The memory chip has to be removed from the phone, the sector of the software, which is responsible for the SIM-Lock, has to be found and edited by the programmer. In older versions of Motorola SIM-Lock could be removed by a special SIM-Card that is called CLONE CARD. All you need it's just a set of cables, programmer and the rarest tool - the programs. They rare, because need to be updated all the time, due to nonstop developing phone models and GSM market.

How legal is to remove a sim lock ?

The legality of the SIM-Lock removing procedure depends on the law of the country. Some countries don't have a strict law that directly forbids this act. It could be declared as An invasion into informative technologies. But from another side, the person that bought the phone is allowed to do with it everything. For example: if you have a TV that supports only one standard of the incoming signal. Nobody can take you to the court if you will install a multi system receiver on it. You can modify it in the way you like. The only thing you will lose is warranty cover. It could be explained in different way, depends on the lawyer.
It gets a different sense when it comes to the illegal export of the mobile devices. They could come legally only from the manufacturers or the official distributors.
Off course GSM service providers are loosing the profits, when the handsets, sold by the 10% of the original price, are crossing the networks.

Will the phone work correctly after unlocking?

As we mentioned before, SIM-Lock is a programming product. If it was removed correctly, it will not have any consequences on a further handset functions.
But sometimes SIM-Lock removing programs are not working correctly, as they are made in unprofessional way. After unlocking by some of these programs, handset could get some malfunctions. The one thing we can say for sure: unlocked handset will not get any problems after some time of using. Other words, if the SIM-Lock wasn't removed correctly then the problems will appear from first moment of work.
Professional unlock will not harm your phone.
There are some samples of software failure after unlocking:
Siemens C 25 security settings are not working (phone lock, PIN lock);
Sagem MC922 call timers are not working, clock resets after charging, charging symbol stays on display after charger was disconnected;
Motorola M3888, 3588 network detect failure;
Ericsson 868 periodically powers off by it self.

How to know, is the handset was unlocked?

By the external attributes:
- if there is a logo of the network provider on the front panel;
- if there is a foreign to the manufacturer language sticker underneath of the battery;
- visible traces of disassembling of the new handset;
Phone's menu has a brand of some network provider (Orange, T-Mobile, Vodafone, Cingular, ATandT etc )
And the last one is a low price.

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