Monday, July 2, 2007

What is Cellphone Unlocking

So, 29th June had arrived and passed. And with it Apple started selling its iPhone, which has created an unmatched hype, unprecedented in the history of cellphones. iPhone is the properitory technology and it works only with one particular telecom service provider.

In this situation, the question becomes highly relevant, What actually is Cellphone Locking and for that matter, Unlocking.

Cellphone UnlockingCellphone Unlocking

Every GSM compatible cellphone has a unique ESN number associated with it, with which it can be identified. On the other hand the SIM, Subscriber Identification Module, is programmed by the Telephony service provider to identify the subscriber. Two are not to be confused. ESN identifies the handset, while SIM identifies the subscriber..

When the telecom service provider bundle the handsets alongwith the telephony service, they lock the SIM. i.e. they program the handset in such a way that it can only be used with a particular SIM. This process is called Handset locking. The benefit is to the telephony service provider, as now the subscriber is tied to them, and will have to change the handset, if he wished to subscribe to any other service provider, which he may not like to do.

Breaking this programming code, so as to enable the handset to work again with any other service provider is called Cellphone Unlocking.

But how Cellphone Unlocking is done ?

There are two ways.

  1. Many handsets can be unlocked simply by keying a secret code into it. The code is usually a unique number only for that particular phone, based on its serial number (what is called its IMEI) and the service provider who locked it. There are many companies, who hack these codes, and sell it to you, sometimes for a fees as low as $5.
  2. Other types of phone need their 'firmware' - their operating system software - to be rewritten to remove the lock. This requires connecting the phone via a special data cable to a special programming unit. This can be done only by professionals.