Elgato Thunderbolt™ Dock is designed to expand the inputs and outputs of your computer. Data flows between connected peripherals and your computer.
Elgato Thunderbolt™ Dock doesn't enable connected devices to communicate with each other on their own.
Data does not flow directly from one port to the other without first involving your computer.
For example, if you connect an iPad via USB, and a display using HDMI, then Elgato Thunderbolt™ Dock doesn't act as a video output device for the iPad - the iPad screen can't be mirrored onto that display.
Instead, the connected iPad can communicate with your computer over USB, such as for synching data. The connected HDMI display will act as an extra monitor for your computer.
Elgato Thunderbolt™ Dock doesn't enable connected devices to communicate with each other on their own.
Data does not flow directly from one port to the other without first involving your computer.
For example, if you connect an iPad via USB, and a display using HDMI, then Elgato Thunderbolt™ Dock doesn't act as a video output device for the iPad - the iPad screen can't be mirrored onto that display.
Instead, the connected iPad can communicate with your computer over USB, such as for synching data. The connected HDMI display will act as an extra monitor for your computer.