What does it mean to activate an unlocked phone? The answer requires a bit of history. Back in the old days of CDMA networks which did not use SIM cards, activating a cell phone meant making the phone active on a carrier network. Because the mobile number has to be baked into the phone, activation was the procedure that linked a specific cell phone to a specific customer account and phone number.
Fast forward to the twenty-first century when CDMA networks are gone and we all use GSM phones that require SIM cards, cell phones aren’t activated. It is the SIM card that has to be activated so that it can register with the network when it is inserted into a phone and the phone is switched on.
Americans still loosely talk about activating a phone, but in reality, it is the SIM card that has to be activated. If you have an already activated SIM card, you can put it into your unlocked cell phone right away at the point of purchase without any activation process required with your carrier.
Strictly speaking, when you activate an unlocked phone on your carrier, it is the SIM card that is activated (if new), not the device. If you have an already active SIM card, just put it into your new unlocked phone, power it on, and start using it.
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If you activate an unlocked phone on your carrier, does the phone become locked?
Not at all. If you purchased an unlocked phone, it remains unlocked on whatever carrier you use it. A carrier cannot remotely lock it, nor would they be allowed to do so.
Carrier network locked phones are phones that the carrier has modified and made available to subscribers, usually at a discounted price through a contract to keep those subscribers on their network. Hence the network lock. A phone that is locked to Carrier A can only be used on that carrier. If you put a SIM card from any other carrier in it, the phone will be unable to connect to their network. That is why it is called a network locked phone.
Once you have paid off your contract, you can request your carrier to unlock the phone, and they will do so. The phone becomes unlocked, freeing it for use on any other carrier.
Can you activate a phone without a SIM card?
As already explained at the beginning of this article, cell phones aren’t activated. It is the SIM card that has to be activated so that it can register with the network when it is in a phone and the phone is switched on.
Activation of the SIM involves associating the SIM card ID number with a specific cell phone number and account. If the SIM is moved to another unlocked phone then the account and cell phone number will move to that second phone.
An activated SIM card can be used in any compatible unlocked phone. An unactivated SIM card is a dud – completely useless.
A SIM can be used in a locked phone if the phone is locked to the same network that issued the SIM card. If the phone is locked to a different network from the SIM card’s carrier, the SIM card is useless inside that phone.
If yoi are buying an iPhone, you will likely be interested in finding out the different kinds of unlocking available for iPhones.