Презентация на тему Communications and i

role in society.

of the principles of building phone systems. Telephony allows you to organize (connect)

and to local, intra-, inter-city and internationaltelephone calls and send faxes, as well as to establish a modem connection in real time.

Telephone Communications.

Computer telephony
Computer telephony is a technology in which the computer plays a central role

in the management of telephone calls, and in the implementation of the transmit and receivephone calls.

Radio-telephone.
Under the wireless radio communication understand the telephone system, which does not require complex engineering work on the laying of

expensive telecommunicationsand support them in working order.
Communication can be organized quickly and regardless of the terrain and weather conditions (although the weather conditions and terrain may have a direct impact on the quality of communication).

need to create a wide network of mobile telephone communications in a fairly strict limits on

the availablebandwidth. Currently, mobile communication is used in more than 140 countries on all continents of the globe. Russia, too, was among the countries that use cell phones. In Russia, mobile communications began to be introduced in 1990, Al 1991 began its commercial use.Currently in Russia there are about 160 million subscribers (at the end of 2006 - 160million).

recommended where the deployment of cabling is impossible or economically unfeasible. Thanks to the handover,

users can roam between access points to the coverage Wi-Fi network without breaking the connection. Developed by a consortium of Wi-Fi Alliance standards-based IEEE 802.11.

type of radio communication, based on the use of artificialearth satellites as repeaters. Satellite

communication is between the earth stations that can be both fixed and mobile. Satellite communications is the development of the traditional microwave transmissionby making the repeater to a very high altitude (tens to hundreds of thousands ofkilometers). Since the zone of visibility in this case - almost half the globe, the need forrepeaters in the chain is no longer - in most cases and one.

regret!