How to unlock a mobile phone and check network compatibility?

When y'all purchase a telephone from T-Mobile, Sprint, and AT&T; they offer yous a subsidized telephone bargain in exchange for a 2-year (or 30-months) contract. They too lock your phone, then that you cannot have the phone to another carrier. To use the phone you bought from Verizon on the AT&T network (or vice versa), you'll have to unlock your telephone. The U.s.a. carriers used to lock your telephone for years, only with the "Unlocking Consumer Choice and Wireless Contest Act", y'all take to right to unlock your phone if you meet their "Unlocking Policy".

The easiest fashion to unlock your phone is by contacting your telephone carrier. Each carrier has a unlike unlock policy, but you have to encounter the following requirements to exist eligible:

  • Your phone must be paid off.
  • Your account with your carrier must be in skilful standing.
  • Your phone has not been reported lost or stolen.
  • Your phone mube exist active on the network for X number of days.
  • Carriers cannot lock a prepaid phone plans for more than than 12 months.

To unlock your phone, your carrier will verify your identity past request your account number, phone number, terminal 4-digits of SSN, and IMEI, MEID, or ESN number of your phone. The following is the carrier-specific unlock policy.

  • AT&T requires you to be with them for sixty-days earlier they unlock your phone. You can make a unlock request online by visiting Unlock your device page. Information technology generally takes nigh 2-days to fulfill your request. Prepaid phone plans will require 6-months of service earlier you can unlock the phone.
  • Verizon does not lock your 4G LTE devices, so they should already be unlocked. Some sometime 3G iPhones may be locked, just you tin can either employ the unlock code "000000" or "123456", or call their customer service for help.
  • T-Mobile requires you to have service with them for xl-days. For prepaid phones, y'all can unlock after 12-months or after refilling $100 in your plan. You lot tin request a device unlock by using their device unlock app.
  • Sprint will automatically unlock your phone once it's paid off. Otherwise, yous'll require l-days of service before you tin request to exist unlocked.

Active duty military people can call the carrier's customer service, and have their phone unlocked without brake. However, you'll accept to prove your active deployment in the US military.

Is it legal to pay 3rd-political party company to unlock your phone?

Every phone has a unlock code that removes restrictions on where it tin exist serviced, and they are available from the manufacturers. Carriers proceed unlock codes in their database and unlock phones when they become eligible to be unlocked. Some of those unlock codes are stolen and sold in the blackness market (or dark spider web) and monetized by unauthorized persons (or companies). Information technology is illegal for them to sell "stolen" unlock codes. Although information technology is not illegal for yous to buy the lawmaking, it may pause your contract term with your carrier. It is always best to use your carrier to unlock your telephone, and never buy an unlock lawmaking from a third-political party.

How to find if my phone is locked?

You can check if your telephone is unlocked by looking at your telephone settings.

  • On iPhone, become to Settings -> General -> Well-nigh. There is a "Carrier Lock" value showing "No SIM restrictions" if your phone is unlocked.
  • On Android, go to Settings -> Connections -> Mobile Networks -> Mobile Operators. If you uncheck "Select automatically", and meet other operators like AT&T, T-Mobile, Sprint and Verizon; you phone is unlocked.

Unlocked Status
Android ll (Left), iOS 14.4.i (Correct)

What are GSM, CDMA and LTE?

There are two mobile technologies used in 2G and 3G networks, and they are GSM (Global Organisation for Mobiles) and CDMA (Code Division Multiple Admission). The newer technology uses LTE, then GSM and CDMA don't thing but for backward compatibility reasons they are still around. In the USA, AT&T and T-Mobile are using GSM while Sprint and Verizon are using CDMA. All United states Carriers (AT&T, T-Mobile, Dart, and Verizon) switched to 4G LTE, but some voice calls were still going through 2G and 3G networks. With US carriers supporting phonation over 4G, the distinction volition go abroad and every service will be delivered on 4G and 5G technologies.

Ane notable difference between the GSM and CDMA is the employ of SIM cards. GSM uses the SIM (Subscriber Identity Module) card to identify the subscriber (i.e. phone number) while CDMA doesn't use a SIM carte considering the information is integrated into the phone. A CDMA carrier like Verizon does non crave a SIM card, but they utilize it to enable LTE so phones that are operating in CDMA technology may have a SIM carte du jour slot.

How can I tell if my telephone volition work on Carrier A?

In order for a phone to work with a particular carrier, the following three things must be compatible.

  • Radio engineering: GSM or CDMA. With 4G and 5G, everyone volition be on the aforementioned engineering science but older technologies are still supported.
  • Frequency bands: Each carrier uses particular frequency bands, and the phone must support that band.
  • Radio channels: Carriers operate in different radio channels, and the phone must support the carrier aqueduct to be used in their network.

Well-nigh newer phones support both GSM and CDMA as well every bit the newer LTE, but frequency bands and radio channels may non exist compatible on international borders. Your Samsung Galaxy S20 used with Sprint in the USA, may not work with SKT operator in Korea. Thus, Samsung produces 6 unlike models of Galaxy S20 meeting different frequency bands and channels.

How can I tell if my phone uses GSM or CDMA? In that location are a couple of ways yous can find its mobile applied science.

  1. Expect at your "Well-nigh" settings. On iPhone, get to Settings -> General -> About. On Android, get to Settings -> About Phone. If your setting shows an IMEI number then information technology's GSM, and if information technology shows a MEID or an ESN number then it'southward a CDMA. If information technology has both, then it supports both GSM and CDMA.
  2. Look upwards the model number of your phone on Google.

How can I tell if my phone will piece of work with a detail carrier? The side by side affair that y'all'll need to check is the frequency band and the channels existence used. If yous look up the model of the phone and carrier's spec sheet, you'll be able to find if your phone is compatible with the carrier. Or, yous may check with a compatibility check exam with your IMEI or MEID.

  • T-Mobile: Enter your IMEI number (GSM), and it will tell you if your phone is compatible. Dart is at present T-Mobile, so new customers will be offered through the T-Mobile GSM plans. The existing Dart customers can stay on CDMA network.
  • AT&T: Enter your device type and IMEI, and AT&T will permit yous know if it's compatible.
  • Verizon: Verizon supports both IMEI (GSM) and ESN or MEID (CDMA) number.

The compatibility check is one slice of the puzzle, and the other puzzle is the "unlocked" status of your telephone. Your telephone must be unlocked in order for it to exist used in a network other than the carrier who locked it.

Does your phone back up Dual SIM cards?

There are a few telephone models that support dual SIM cards. Dual SIM cards allow you to accept two separate phone lines with two phone numbers. You may use 1 for work and the other for personal, and non have to carry two phones. You may also take your phone to other countries, and employ the second SIM slot for local carrier service. Yous may choose to utilize ane SIM as the primary, and the other for secondary so that if y'all make a call it will use your primary phone line. You may besides selectively pick a secondary phone line to make a phone phone call. You'll receive a call and SMS from both phone lines.

  • iPhone XS, xi and 12 models support dual SIMs. The main one is integrated into your phone (eSIM or digital SIM), and the secondary one is populated in a nano-SIM slot. With iOS xiii and later on, both phone numbers can send and receive voice, facetime, SMS, MMS, and iMessages. On the iPhone 12 using in Dual SIM style, 5G is non currently supported and will fall dorsum to 4G LTE.
  • Some models of Samsung Milky way S(20, 20+, Ultra), Z Flip, Note (x, 10+), S(10, 10+) and Galaxy Fold accept dual SIM slots depending on the country and carrier.

Samsung Dual SIM
Samsung Dual SIM Slots

There are other vendors like LG, HTC, and Huawei that produce phones that support Dual SIMs. You may accept to check their specification canvass to know if a specific model supports dual SIMs.

Conclusion

To determine if your telephone is compatible with a particular carrier, (1) the telephone must be unlocked, (2) must support engineering science whether it's GSM or CDMA, (3) support the frequency ring, and (4) support the radio channels. You can contact your carrier to unlock your phone if you are eligible, and cheque phone specifications to determine if it meets frequency and channel requirements. If you likewise utilize the dual-SIM, yous tin have 2 telephone numbers in a single phone.

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