Tapio comes with Apple's Lightning to USB Camera adapter or USB-C adapter.

Tapio is a native USB switch interface that can be connected to an Apple iOS device using an Apple USB camera adapter.

It accepts industry standard 3.5 mm stereo or mono plugs, and directly interfaces up to two adaptive switches to an iOS device or computer. Tapio is powered from the device, and does not require external power.

A note of compatibility:

Apple iOS Devices have worked with direct connect USB keyboards since the early days of iPhone. However, Apple only officially supports Bluetooth keyboards. For this reason whenever you plug a USB keyboard into an iOS Device, or turn on an iOS Device with USB keyboard connected you will receive a notification or message telling you that it is not supported.

Since Tapio presents itself as a USB keyboard, you will see this message. Simply tap OK directly or scan to and "tap" OK to dismiss the dialog box.