> For the complete documentation index, see [llms.txt](https://smartpossdk.gitbook.io/cloudpossdk/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://smartpossdk.gitbook.io/cloudpossdk/faq/firmware/write-customer-serial-numbers.md).

# Write Customer Serial Numbers

### System Interface for Customer SN

* AIDL Interface: The system offers an AIDL interface to write customer SNs.
* Service Connection:
  * Package Name: 'com.wizarpos.system.settings'
  * Class Name: 'com.wizarpos.system.settings.service.CustomSnApiService'

### Required Permission

* Add Permission: Include 'android.permission.CLOUDPOS\_UPDATE\_CUSTOM\_SERIAL\_NUMBER' in your application to utilize this feature.

### API Usage

* API Function: 'writerSn' is used for writing the customer serial number.

{% code overflow="wrap" %}

```java
int writerSn(String sn);
```

{% endcode %}

Write customer SN.

| Parameters |                  |
| ---------- | ---------------- |
| sn         | the customer SN. |

| Returns |                                                                                   |
| ------- | --------------------------------------------------------------------------------- |
| int     | <p>an int representation of the result.<br>>=0 if success; <br><0 if failure.</p> |

### File Download

Please download the [AIDL file](https://ftp.wizarpos.com/advanceSDK/ICustomSnApi.aidl).

Please download the [demo.](<https://github.com/SmartPOSSamples/CustomSnApiDemo >)


---

# 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 dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://smartpossdk.gitbook.io/cloudpossdk/faq/firmware/write-customer-serial-numbers.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
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.