> For the complete documentation index, see [llms.txt](https://docs.verifone.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.verifone.com/support-nordics/v400m/how-tos/how-to-check-mobile-data-configuration.md).

# How to Check Mobile Data Configuration

Check and fix the mobile data (4G) settings on your V400M — network interface, SIM slot, APN, and SIM card.

{% hint style="info" %}
**Use this when** your V400M uses **mobile data (4G)** and you want to check its mobile data settings are correct — for example, if it won't connect using mobile data.
{% endhint %}

## Before you start

{% hint style="warning" %}
**Mobile data doesn't work if the battery is below 30%.** Charge the terminal to above 30% before you start.
{% endhint %}

## Check the mobile data settings

{% stepper %}
{% step %}

### Open the mobile data settings

1. Press **4** and **6** at the same time, then enter password **1234** and press the **green button**.
2. Select **Administration > Settings > Communication**.
3. Select **Mobile data**.
   {% endstep %}

{% step %}

### Start the network interface

Tap **Start Network Interface**.

* **If the status shows "Successful":** mobile data is working. Check the Network Fallback setting is correct (see the hint below), then you're done.
* **If it fails:** continue to Step 3.

{% hint style="info" %}
**Network Fallback:** go to **Administration > Settings > Network Fallback**. **Default** should be set to **GPRS** (mobile data), and **Fallback 1** should be set to **None**.
{% endhint %}
{% endstep %}

{% step %}

### Check the SIM slot

1. In **Mobile data**, tap **Configuration**.
2. Select **SIM-SLOT**.
3. If it's set to **1**, change it to **2** — or if it's set to **2**, change it to **1**.
   {% endstep %}

{% step %}

### Check the APN

1. Tap **Mobile Settings**.
2. Check the **APN** is set to `verifone.cxn`. If it isn't, enter `verifone.cxn`.
3. At the bottom of the menu, check **SIM SLOT** shows **"Currently selected SIM-slot"**.

Then go back and tap **Start Network Interface** again.

✅ **Status shows "Successful" — stop here.** ❌ **Still failing — continue to Step 5.**
{% endstep %}

{% step %}

### Check the SIM card is in place

1. **Turn the terminal off.**
2. Open the back of the terminal and **take out the battery**.
3. Check the **SIM card** behind the battery:
   * It's sitting **straight**.
   * It hasn't come loose or moved out of place.
   * It's **pushed fully into** the card slot.
4. Put the battery back and close the back.

{% hint style="info" %}
The SIM card can easily be knocked out of position, so it's worth checking carefully.
{% endhint %}
{% endstep %}

{% step %}

### Restart the terminal

Turn the terminal back on, then check mobile data again by tapping **Start Network Interface** — see Step 2. For restart options, see [How to Reboot the Terminal](/support-nordics/v400m/how-tos/how-to-reboot-the-terminal.md).
{% endstep %}
{% endstepper %}

Still not working? See [Mobile Data Is Not Working](/support-nordics/v400m/errors/mobile-data-is-not-working.md) or <mark style="color:red;">contact Verifone Support</mark>.

<details>

<summary>Keywords</summary>

Also called: mobile data settings, 4G settings, GPRS settings, APN, SIM slot, SIM card, start network interface. Search terms: mobile data, 4G, GPRS, APN, verifone.cxn, SIM, SIM slot, network interface, battery 30%.

</details>


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation by asking a question.

Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters:

```
GET https://docs.verifone.com/support-nordics/v400m/how-tos/how-to-check-mobile-data-configuration.md?ask=<question>&goal=<user_goal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.