Communications Equipment

Communication is defined as a process of transferring information from one entity to another. Communication processes are sign-mediated interactions between no less than two elements which share a range of signs and semiotic rules. Communication may also be defined as "the imparting or interchange of thoughts, opinions, or information by speech, writing, or signs". There are different methods of communication the most common being direct speech between humans. Other facilities can enable communication, more specifically communications equipment. In modern times the primary types of communications equipment that are use include telephone, radio, television and the computer via the internet.

Telephone

In an analogue telephone network, the caller is connected to the person he wishes to speak with by switches at a variety of telephone exchanges. The switches will produce an electrical connection between the two users and the setting of these switches is determined electronically when the caller dials the specific number. Once the connection is made, the caller's voice is transformed into an electrical signal using a small microphone in the caller's handset. This electrical signal is then processed and sent through the network to the user at the other end where it is transformed back into sound by a small speaker in that person's handset. Additionally there is a separate electrical connection that works in reverse, allowing both users to converse. The fixed line also combines digital and analogue transmission to enable long distance calls. The fixed line is becoming far less popular because of the advent of the cellular phone which enables users to be completely mobile.

Radio and television

Within a broadcast system, the central high-powered broadcast tower transmits a high-frequency electromagnetic wave to multiple low-powered receivers. This high-frequency wave sent by the tower is modulated with a signal containing visual or audio information. The receiver is then tuned to enable the instrument to pick up the high-frequency wave and a demodulator is used to retrieve the signal containing the visual or audio information. The broadcast signal can be either analogue which means the signal is varied continuously in relation to the information or digital which means the information is encoded as a set of discrete values. Regardless of the method the outcome will be audio if listening to a radio and audio and picture if watching a television.

Internet

The Internet is in actuality a worldwide network of computers and computer networks that are capable of communicating with each other using the Internet Protocol. A single computer on the Internet has a unique IP address that can be used by other computers to route information to it. As a result, any computer on the Internet can deliver a message to any other computer using its IP address. These messages that are sent carry with them the originating computer's IP address allowing for two-way communication. The Internet is therefore, in essence, an exchange of messages between computers. As of 2008, an estimated 21.9% of the world population has access to the Internet with the highest access rates seen in North America with 73.6%, Oceania/Australia with 59.5% and Europe with 48.1%.

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