CertiGuide to A+ (A+ 4 Real)  9  Chapter 13: Basic Networking Terminology       9  Wireless

Wireless 1 Advantages and Disadvantages of Using IR

The signals of the input interface of system are used for modulation of a signal in the open optical channel. The basic concept and problems are the same as with the remote control for the TV. The technology of transfer is based on data transfer by the modulated radiation in an infrared part of a spectrum of light through atmosphere.²⁰⁴

To receive the high-quality data link, it is necessary not only to have good IR-system; it is essential to establish it correctly. There are strict requirements to a successful installation of the systems - to rigidity of direction, taking into consideration trees, surroundings etc. A laser beam may be having a good potential, but for adequate reception of the good characteristics for IR-system, it is advisable to consult the experts.

The competently designed and established system can ensure high quality of the connection channel with a level of availability 99, 1%- 99, 9%. It is typical that the bit mistakes in IR-channel are practically absent. However, it is extremely difficult to receive value higher than 99, 97 % under real conditions. In addition, the reason to that - birds! The laser beam can overcome practically all weather phenomena, but physical barrier he cannot. With the purposes of safe operation, density of a light flow is limited synthetically. As a result if the birds are crossing a beam, this quickly interrupts the channel of transfer. However, there is a real way out – use of multi beam systems. It is more expensive, but justifies additional expenses to gain even better performance. It is necessary to pay for every additional line after a point in constant availability of the channel. Nevertheless, this is true not only for IR-systems, but for all other systems too.

The components of all IR systems of transfer are identical - interface module, modulator of oscillator, optical system of the transmitter, optical system of the receiver, demodulator of the receiver and interface block of the receiver. However, all systems can be divided into two groups by a technological attribute. One group uses semi-conductor IR diodes, and the second uses semi-conductor IR laser diodes for radiation. The main distinction of systems has an effect to their main characteristics - speed and range of transfer. First group is short range systems up to 1 km with speeds up to 20Mbps, second - provides considerably larger range of transfer, depending on weather conditions and requirements to quality of the channel, with speeds up to 622 Mbps or even up to 10 Gigabits/s are in vision....

Wireless 1 Advantages and Disadvantages of Using IR