Many phone handsets are sold via a network operator. The operators sometimes subsidize the cost of the phone and get their money back through the customers use of that network. For this reason, the phone is usually 'locked' to that providers network, to ensure that they see this return.
Phones bought for full price directly from the handset manufacturer are usually sold 'unlocked' - in other words, you can use the phone with any SIM, on any network, in any country. Telestial's handsets are sold unlocked and our SIM cards require an unlocked phone to work.
Often, the best way to tell if your phone is locked or unlocked is to insert a SIM from another provider. Locked handsets will usually display a message to indicate that the phone is locked such as:
If you see one of these messages upon inserting a new SIM card, then your phone is locked. Alternately, you can contact your domestic operator and ask them if your phone is locked or not.
In order to unlock your phone, you will need to contact your domestic service provider. Details of how to unlock a phone are provided on the operators website. There is sometimes a waiting period and/or a fee to pay before your phone is unlocked. Once your phone is unlocked, you are free to use any SIM on any network in any country. It is NOT illegal to unlock your phone!