transmission medium
Transmission media are devices for the transmission of information. Solid, liquid and gaseous materials can be used as media. Typical transmission media are metal, glass, plastic, water, air or the vacuum. The information to be transmitted is transferred using an information carrier. Such an information carrier can be a pressure wave as in sound, a voltage pulse or light pulse, or an electromagnetic wave.
In practice, cables, glass or plastic fibers and also the atmosphere are used as transmission media. In the latter, electromagnetic waves are transmitted. Known to all from radio and television.
In communications technology, a distinction is made between wire-bound and wire-less transmission media. The first group involves cables and optical fibers, which are used in floor cabling, building c abling or off-road cabling. The telephone network and most of the Internet use copper cables and optical fibers. The second group is about wireless transmission technology, where information content is transmitted using pressure, infrared light or electromagnetic waves. Examples of this technology include sound transmission, IR LANs and complete mobile and satellite communications, WLANs, Bluetooth, RFID and many other applications.
If we break down the group of conductor-based transmission media further, we have the copper twisted pairs, which are used in the connection area. Other classic cables are coaxial cables and twisted pair cables. Conductor-bound are also optical waveguides in the form of glass and plastic fibers.
The way in which the information is transmitted on the information carrier depends on the transmission medium. In order to be able to transmit as much information as possible, transmission media with high and highest bandwidths are developed. In addition, the information is encoded and modulated before transmission.