I think I should remind people that near field communications exists.
http://www.techradar.com/us/news/pho...r-phone-948410
It's around 13.5MHz and no license is required.
http://electronics.howstuffworks.com...unication4.htm
Also you could craft a way to communicate using QR codes.
Put it on the display and scan it with the smart phone: zero wireless.
You can encode - a lot - of data just like that.
Picture a computer monitor used for all QR code dots
In both cases the Internet is not involved.