The Dish Joey is a player, just like a Roku. You can't plug one player into another, with a few exceptions where a player has an HDMI input jack, which I doubt the Joey has. You plug your Joey and your Roku directly into a TV display, or alternately into an AV receiver that has HDMI inputs and does the switching and send the video out via HDMI to the display.
Dan
Roku Community Streaming Expert
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