> ## Documentation Index
> Fetch the complete documentation index at: https://docs.paybyrd.com/llms.txt
> Use this file to discover all available pages before exploring further.

# PAX peripherals Kit

To develop an app that communicates with PAX terminal peripherals (such as the printer or camera), use the Neptune Service and PAX's NeptuneLiteAPI.

## Neptune Service

This application manages the devices in PAX PayDroid-based terminals. The peripherals/devices include the printer, the card reader, the contactless card reader, etc.

If you are developing an app that runs inside the PAX POS, Neptune Service must be installed on the terminal before you call the NeptuneLiteApi.

## Neptune Lite API

Once Neptune Service is installed, you can use the NeptuneLiteApi to access the GPS, speaker, cameras, and other peripherals.

The NeptuneLiteApi provides the APIs of the NeptuneService. This currently contains only the Device Adapter Layer module (DAL).

The DAL provides uniform APIs for device operations, abstracting the differences between terminal models.