I mentioned in another post that Zenith sued Admiral over these remote sets claiming they infringed on Zenith's patents for the Space Command. Zenith ultimately won and forced Admiral to pay royalties on them.

Here is a copy of the judgment in the appeals court where Zenith won. Interesting reading as you can see how Admiral tried to fudge their way through it, and also redesigned their remote in 1960 to try to avoid it. http://www.leagle.com/decision/19611...%20CORPORATION