> 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/p400-two-piece-sa/how-tos/how-to-locate-the-serial-number.md).

# How to Locate the Serial Number

Find the serial number on your P400 Two-Piece — on the label underneath, or in the menu on each unit.

{% hint style="info" %}
**Use this when** you need your terminal's serial number — for example, when setting up the terminal or contacting Verifone Support.
{% endhint %}

Your P400 Two-Piece has two units, and **each unit has its own serial number**:

* **Customer unit (P400)** — the unit your customer uses to pay.
* **Operator unit (V400c)** — the unit at the till.

You can find the serial number on the label underneath each unit, or in each unit's menu:

{% tabs %}
{% tab title="On the label" %}

1. Carefully turn the unit over so you can see the underside.
2. The **serial number** is printed on the label on the **underside** of the unit.
3. If you need both serial numbers, repeat on the other unit. Make sure you note which serial number belongs to which unit.
   {% endtab %}

{% tab title="Customer unit menu" %}

1. On the customer unit, press **4** and **6** at the same time, then enter password **1234** and press the **green button**.
2. Select **Terminal information**.
3. Select **Version information**.
4. Select **Hardware**.
5. The **serial number** is shown here.
6. Press the **red button** to close the menu.
   {% endtab %}

{% tab title="Operator unit menu" %}

1. On the operator unit, press **#**. No password is needed.
2. Select **Terminal information**.
3. Select **Version information**.
4. Select **Hardware**.
5. The **serial number** is shown here.
6. Press the **red button** to close the menu.
   {% endtab %}
   {% endtabs %}

<details>

<summary>Keywords</summary>

Also called: serial number, S/N, find serial number, terminal serial, device serial. Search terms: serial number, S/N, underside, label, terminal information, version information, hardware, customer unit, operator unit, P400, V400c.

</details>


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