ENC Mobile US SIM shows no signal? It is not faulty: turn on Wi-Fi Calling in 3 steps to receive texts (2026)

Why there is no signal: this SIM does not use the cellular network here

ENC is a brand of the US carrier ENC Mobile. This SIM runs on the T-Mobile network and gives you a real US +1 mobile number, not a VoIP number. It does not roam in China and its plan has no data, so seeing "No Service" or no signal bars after inserting it is normal.

It reaches the T-Mobile network through the Wi-Fi you are connected to. Once Wi-Fi Calling is on, texts and calls go over Wi-Fi, regardless of mobile signal.

Four things to check first

• check_circlePhone: iPhone 6S or later, Chinese or international model. Locked, jailbroken and SIM-adapter ("卡贴") phones cannot turn it on; for other brands, email support before buying.
• check_circleWi-Fi: connect to a stable Wi-Fi network. Mobile signal does not help; this SIM works only over Wi-Fi.
• check_circleNetwork environment: turning on Wi-Fi Calling for the first time requires an overseas network environment, as required by the supply channel.
• check_circleSoftware: update your iPhone first. Apple says Wi-Fi Calling needs the latest software.

Turn on Wi-Fi Calling in 3 steps (about 5 minutes)

1. 1

   Connect to Wi-Fi and check the network environment

   Connect your iPhone to Wi-Fi and make sure you are in an overseas network environment. The product information requires this for the first activation; without it, Wi-Fi Calling may not turn on.
2. 2

   Insert the SIM and turn on Wi-Fi Calling

   Insert the SIM and open Settings > Cellular > Wi-Fi Calling (on some iOS versions it is under Settings > Phone). On a dual-SIM iPhone, choose the US number first, then turn on Wi-Fi Calling on This iPhone and tap Enable. If asked for an emergency address, enter or confirm it.
3. 3

   Wait 3–5 minutes and check the status bar

   After 3–5 minutes, open Control Center. When Wi-Fi appears next to the carrier name, it is working. Send a text to the number from another phone to confirm.

Will not turn on? Check these 7 things

Work through them in order and wait 2 minutes after each step, as Apple recommends; switching too fast hides whether a step worked.

1. 1

   Confirm the phone qualifies

   Locked, jailbroken and SIM-adapter phones cannot use Wi-Fi Calling. Rule this out first.
2. 2

   Confirm the switch is on for the US number

   On a dual-SIM iPhone, select the US number under Cellular and check that its Wi-Fi Calling is on, not the other SIM's.
3. 3

   Check the network environment for the first activation

   The product information requires an overseas network environment for the first activation. Once that is in place, turn the switch off and on again.
4. 4

   Restart the iPhone

   Turn it off and on, then wait 2 minutes and check the status bar.
5. 5

   Try another Wi-Fi network

   Apple notes that not all Wi-Fi networks support Wi-Fi Calling. If home Wi-Fi fails, try work or a personal hotspot.
6. 6

   Turn Wi-Fi Calling off and on

   Switch off Wi-Fi Calling, wait 2 minutes, then turn it on and enable it again.
7. 7

   Reset network settings

   Settings > General > Transfer or Reset iPhone > Reset > Reset Network Settings. This erases saved Wi-Fi passwords, so do it last.

If all 7 steps fail, email LarkSIM support with your order number, US number and screenshots of the settings page. Contact details are at the bottom of the product page.

Why PayGo shows signal and ENC does not

Many people judge ENC by their PayGo experience and assume no signal means a faulty SIM. Common US SIMs simply receive texts in China in different ways:

ENC's advantage is that you need no US trip to activate or enable roaming; the SIM ships to China and works there. The trade-off is that it depends on Wi-Fi. For the full comparison, see giffgaff disconnected or Tello banned: which SIM next.

5 limits to know before you start

• check_circleNo Wi-Fi, no texts: when Wi-Fi is off or disconnected, this SIM cannot receive texts or calls.
• check_circleYour network decides: whether Wi-Fi Calling connects depends on your network environment. Failing to connect for network reasons is not a SIM fault.
• check_circleCodes are not guaranteed: ordinary texts work, but whether a service sends you a verification code depends on its rules and your IP environment.
• check_circleRandom number: the carrier assigns the number at random; it may have been used before and cannot be chosen or changed.
• check_circleRenew on time: there is no self-service top-up; ask support to top up before expiry. The number is cancelled after 30 days suspended.

Once your phone and use case fit, Buy the US T-Mobile physical SIM (ENC).

FAQ

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