If you want to use Zattoo on a Smart TV without an AndroidTV operating system, you can use the Nvidia Shield Box, for example, that practically works on every TV or screen that supports HDMI. Nvidia Shield can be connected directly to the TV or to the receiver.
On the market, there are many differing streaming boxes with Android, that are not supported by Zattoo. Those are boxes that have Android as an operating system, but they are not AndroidTV. On those devices you can find our mobile app that was not optimized for big screens.