If you are looking for mobile technology from long ago, the earliest concept I can recall is from Get Smart, the Shoe Phone. Likewise, if you wanted an early concept for how to have a secure conversation, there was the….Cone of Silence. As wacky as these conceptions are there was prescience in both of them – the need was there even if the product didn't deliver on filling it. The show was also a riot. I bet it would still be funny if viewed today. You can get the complete series as a boxed set. And loving it.