Infrared Transmission

Infrared Transmission

You use an infrared communication system every time you control your television with a remote control. The remote control transmits pulses of infrared light that carry coded instructions to a receiver on the TV. This technology also can be adapted to network communication.

Four varieties of infrared communications are as follows:

Broadband optical telepoint. This method uses broadband technology. Data transfer rates in this high-end option are competitive with those for a cable-based network.
Line-of-sight infrared. Transmissions must occur over a clear, line-of-sight path between transmitter and receiver.
Reflective infrared. Wireless PCs transmit toward a common, central unit, which then directs communication to each of the nodes.
Scatter infrared. Transmissions reflect off floors, walls, and ceilings until (theoretically) they finally reach the receiver. Because of the imprecise trajectory, data transfer rates are slow. The maximum reliable distance is around 100 feet.

Infrared transmissions typically are limited to within 100 feet. Within this range, however, infrared is relatively fast. Infrared’s high bandwidth supports transmission speeds of up to 10 Mbps.

Infrared devices are insensitive to radio-frequency interference, but reception can be degraded by bright light. Because transmissions are tightly focused, they are fairly immune to electronic eavesdropping.