The components of the system can be classified into three categories, namely, the three major hardware devices of the telecommunication system-terminal equipment, transmission equipments and switching equipment.
Folding Terminal Equipment
Typically installed at the user's office, provides the device (the telecommunications endpoint) that the user implements the functionality necessary to access the protocol. Its role is to convert voice, text, data and images (stationary or active) information into electrical signals or electromagnetic signals to send, and the received electrical or electromagnetic signals to restore the original voice, text, data and image information. Typical terminals include telephones, telegraph, mobile phones, wireless pagers, data terminals, micro-computers, fax machines, televisions, etc. Some terminals can also be a local or small telecommunications system, they to the public telecommunications network, as a terminal device access, such as user switches, ISDN terminals, LAN, office automation systems, computer systems and so on.
Folding Transmission Equipment
A device that transmits an electrical or electromagnetic signal from one location to another. It forms the transmission link in the telecommunication network, including radio and cable transmission equipment. Radio transmission equipment includes shortwave, ultrashort wave, microwave transceiver and transmission system, as well as satellite communication system (including satellite and earth station equipment). Cable transmission equipment has overhead open-wire, cables, optical cables, underground cables, coaxial cables, optical cables, submarine cables, optical cables and other transmission systems. A variety of modulation and demodulation equipment, pulse code modulation equipment installed in the above system. Terminal and relay ancillary equipment, monitoring equipment, etc., also belong to the transmission equipment.