They do this with or without the knowledge of customers and the discounts and offers offered to them is due to contract terms they enter with a carrier whereby they would use services of only the chosen carrier for a specific period of time. Usually, mobile manufacturers sell phones to customers at a discount and other special offers with a market oriented approach.

The mobile manufacturers block it by country code or by the particular network provider or thirdly by the mobile identification number of region specific area within a country. Here, you will find that when a locked phone is purchased by you it is restricted in the following ways. In other words, sim network unlock is done primarily to avoid consumers misusing a mobile manufacturer’s special offers while purchasing the phone. This restriction is in-built when you purchase your phone from mobile manufacturers and is seen in both GSM and CDMA phones. Sim network unlock pin is a form of restriction carried out by mobile manufacturers so that users do not exercise too much choice that enables them switch from one country to another or from network to network.

T mobile network unlock code