Sending signals in the future could be done through lights in the room.
LED lights have been gaining popularity over the past few years for the benefits they bring in terms of energy saving and environmental friendliness, which in itself is a great thing. The fairly unassuming light source could make even more of a name for itself with the potential to transmit data at speeds up to 3 gigabits.
A German institue called Fraunhofer Institute has been experimenting with rapidly blinking LED lights that can transmit data through the air. The speed of 3 gigabits mentioned above can be achieved by combing three lights of different colours, with each light able to transmit 1 gigabit/second.
The institute thinks the lights will be most useful in high interference locations and events, such as a trade shows and industrial settings. As the technology is refined, they believe it could be used to transmit data from street lights to passing cars and other futuristic situations.
Potential drawbacks include the fact they are ineffective outside, require a line of sight and have significantly reduced speeds as your increase the distance (100Mbps at 20 meters). Plus the fact if it were used with a laptop or phone you would have a consistently blinking light to deal with.