# Device Types **Device Types** extract, transform and normalize the data sent from the device. To reduce energy consumption and keep the data packets as small as possible, **LPWAN devices** send their data via a payload encoded in **hexadecimal** format. This differs from other protocols that define standard data payload formats and communicate through structured data such as **JSON** or **XML**.\ In the case of **HTTP** or **MQTT**, the payload generally does not have a predefined structure. Therefore "passthrough" can be selected when a **Data Flow** gets created. More information about payload decoding can be found in this [blog](https://akenza.io/blog/payload-decoding). ### Device Type Library Akenza offers a variety of predefined **Device Types** available on the [Device Type Library](https://akenza.io/features/device-type-library). The logic is predefined based on device specifications. No additional processing logic will be required. The **Device Type Library** can be accessed when creating a Data Flow. **Passthrough** device types pass along the data to the output connector exactly the same way it was received by the **Device Type**. This is useful for devices that already send a **JSON structure** and do not require any additional processing. If the payload needs to be decoded of a device, which is not available on the **Device Type Library**, a [**Custom Device Type**](https://docs.akenza.io/get-started/device-type) (CDT) can be created. This CDT gets available on the organization level. ![Device Type Library within a Data Flow](/files/daIbfgATY1oSxawVjlea) --- # Agent Instructions: 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://docs.akenza.io/akenza.io/get-started/your-data-flow/device-type.md?ask= ``` 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.