Regardless of how we choose to remove a phone’s SIM lock, whether we use our network services, an IMEI Unlock service, an unlock code, or a SIM chip (like RSIM), it’s essentially a GSM unlock.
So let’s see what exactly the SIM lock is, what is the best way to remove it and how to ensure success.
Updated on June 11, 2020.
What is GSM Technology?
GSM (Global System for Mobile communications) is a special kind of mobile phone technology which is also used on tablets. It basically works by placing the Carrier’s account information on a SIM card. When you insert it in a GSM phone allows you to make calls, send text messages, and surf online.
Τhe first prerequisite for using your SIM card with a mobile phone is to support GSM.
Most manufacturers prefer GSM technology over CDMA which is the other side of the coin since it doesn’t use SIM Cards.
The vast majority of iPhones are GSM phones, though there are CDMA versions sold by CDMA Networks like Sprint and Verizon (until the end of 2019 since Verizon became a GSM network in 2020) in the States.
But what does all this have to do with the GSM Unlock?
The GSM Lock (or, if you prefer SIM Lock)
So, the SIM Card is linked to your account and needs a GSM smartphone to work but there’s more to it.
The second requirement is that the cellphone must be unlocked.
All Carriers want you to use your phone with their SIM cards ONLY and this is why SIM Lock exists.
For example, if you buy an iPhone from US T-Mobile, you can only use it with T-Mobile SIM cards because they will lock it as soon as you purchase it.
In fact, the iPhone is also linked with the Carrier through its IMEI number. All networks share a huge IMEI database called GSMA. This way, every smartphone is fully identified and verified at all times. If it appears as locked on a network then you are stuck with it.
What does GSM Unlocked mean?
Switching between service providers and using your iPhone with local GSM networks when you travel abroad is only possible with GSM Unlock.
Basically all we have to do is change the SIM Lock status of the phone from Locked to Unlocked within the GSMA database. The SIM unlock process is actually quite simple and you don’t need to be a hacker or have any technical knowledge. You just have to choose the right service.
1. GSM Unlock through the Carrier (Available for all mobiles)
The first option should always be the network GSM Unlock services since they are almost always free. The problem lies in the complex policies they use to make your cellphone almost never compatible with unlocking.
However, you have nothing to lose before trying out the following paid services. Here’s a guide on how to unlock an AT&T iPhone via the network.
2. GSM Unlock Codes (Available only for Android Phones)
In this case, you just have to enter a numeric code. There are various third-party companies that provide these codes usually costing from $5 to about $25, depending on the smartphone manufacturer, the model as well as the locking network.
3. IMEI Unlock (Available only for iPhones)
The most popular GSM Unlock method. Using the iPhone’s IMEI, this service permanently unlocks the device. It usually takes 5 to 12 days to complete and the price ranges between $20 and $200.
4. GSM Unlock SIM Card Chips (Available only for iPhones)
Personally, I am not overly excited about this method as not only is temporary but it can even damage the device.
Squeezing your SIM Card with the SIM interposer into the SIM Tray is not a very good idea.
Although extremely cheap, the same is true for their manufacture as they are often defective. Finally, you have to be very careful with which one to choose since they are different per network, iPhone model, and even iOS version.
Can I unlock any GSM phone?
The answer is no. Before you spend your money on the first GSM Unlock service that looks good to you, it is extremely important to know the exact IMEI status of your phone.
As I explained problems like the blacklist, outstanding financial balances, an active contract or warranty, and many more require special IMEI Check and Unlock services.