Direct communication between cell phones using flashlight and camera

Aside from Wi-Fi and Bluetooth near field communication (NFC) cell phones can communicate (theoretically) by sending signals with a camera flashlight and receiving them with a camera. As alternative, the phone's screen can be used as a transmitter.


Here is document (a copy) and video describing similar communication method.

Also there are mysterious Morse Code apps I have to explore: http://www.androidzoom.com/android_applications/morse+code+communication

DECT cordless phones can talk to each without the base station

In discussion http://www.physicsforums.com/showthread.php?t=517690 user xts says:

"You may take a pair of handsets from your home for a picnic and talk in a walkie-talkie mode, even if handsets are out of range of your base station."

Interesting idea. I have to give it a try.