# How it fits together _Mouse, box, and PC_ The box has two chips joined by an internal link, plus a third port for your program. The clone is a copy of the real mouse's USB identity. | Part | Role | | --- | --- | | Host chip | Reads the real mouse. | | Device chip | Presents the clone to the PC and merges your input into what it reports. | | Link | Passes data between the two chips. | ``` real mouse game PC | ^ | USB3 | USB1 v | +-----------+ +-----------+ | host chip | ---- link ---> |device chip| +-----------+ +-----------+ ^ | USB2 (CH343 serial) | control PC ``` Three connections: | Port | Connects to | | --- | --- | | [`USB3`](/native/hardware.md) | The real mouse. | | [`USB1`](/native/hardware.md) | The PC receiving the mouse. | | [`USB2`](/native/transport.md) | The program driving the box, over a [CH343 serial link](/native/transport.md). | That program speaks the [binary protocol](/native/frame.md), sending [movement](/native/commands/move.md), [button](/native/commands/inject.md), and [scroll](/native/commands/move.md#wheel) commands. ## What the PC sees _A real mouse, plus your input_ To the PC the clone is the same model of mouse, with the same buttons and capabilities. Your input adds to the real mouse's input rather than replacing it ([Injection Model](/native/injection.md)), so the physical mouse keeps working either way. | When your program | The box | | --- | --- | | Sends input | Layers your movement, scroll, and button state onto the real mouse. | | Goes quiet | Returns to plain passthrough, just a wire, per the [safety rule](/native/injection.md#safety). | ## Two computers _A separate driver host_ Your program on [`USB2`](/native/transport.md) runs on a different computer from the one receiving the mouse on [`USB1`](/native/hardware.md). > **Note** > > See [Hardware](/native/hardware.md) for the ports and how to wire them, including the one pairing to avoid.