|
Aerial Insert
In telecommunications an aerial insert is a segment of cabling that rises from ground to a point above ground, followed by an overhead run, e.g. on poles, followed by a drop back into the ground. An aerial insert is used in places where it is not possible or practical to place a cable underground. Aerial inserts might be encountered in crossing deep ditches, canals, rivers, or subway lines. Aerial inserts can be found for the same reason also in underground power transmission lines. However for this purpose, the aerial insert is in most cases realized as classical overhead line. It is also possible that a powerline consists of multiple underground and overhead sections of different length. See also * Aerial cable An aerial cable or air cable is an insulated cable usually containing all conductors required for an electrical distribution system (typically using aerial bundled cables) or a telecommunication line, which is suspended between utility poles o ... References T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telecommunications
Telecommunication is the transmission of information by various types of technologies over wire, radio, optical, or other electromagnetic systems. It has its origin in the desire of humans for communication over a distance greater than that feasible with the human voice, but with a similar scale of expediency; thus, slow systems (such as postal mail) are excluded from the field. The transmission media in telecommunication have evolved through numerous stages of technology, from beacons and other visual signals (such as smoke signals, semaphore telegraphs, signal flags, and optical heliographs), to electrical cable and electromagnetic radiation, including light. Such transmission paths are often divided into communication channels, which afford the advantages of multiplexing multiple concurrent communication sessions. ''Telecommunication'' is often used in its plural form. Other examples of pre-modern long-distance communication included audio messages, such as coded drumb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telephone Cable
A telephone line or telephone circuit (or just line or circuit industrywide) is a single-user telecommunication circuit, circuit on a telephone telecommunication, communication system. It is designed to reproduce speech of a quality that is understandable. It is the physical wire or other signaling medium connecting the user's telephone apparatus to the telecommunications network, and usually also implies a single telephone number for invoice, billing purposes reserved for that user. Telephone lines are used to deliver landline telephone service and Digital subscriber line (DSL) phone cable service to the premises. Telephone overhead lines are connected to the public switched telephone network. The voltage at a subscriber's network interface is typically 48 V between the ring and tip wires, with tip near ground and ring at -48 V. In the United States In 1878, the Bell System, Bell Telephone Company began to use two-wire circuits, called the local loop, from each user's tele ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ditch
A ditch is a small to moderate divot created to channel water. A ditch can be used for drainage, to drain water from low-lying areas, alongside roadways or fields, or to channel water from a more distant source for plant irrigation. Ditches are commonly seen around farmland, especially in areas that have required drainage, such as The Fens in eastern England and much of the Netherlands. Roadside ditches may provide a hazard to motorists and cyclists, whose vehicles may crash into them and get damaged, flipped over, or stuck and cause major injury, especially in poor weather conditions and rural areas. Etymology In Anglo-Saxon, the word ''dïc'' already existed and was pronounced "deek" in northern England and "deetch" in the south. The origins of the word lie in digging a trench and forming the upcast soil into a bank alongside it. This practice has meant that the name ''dïc'' was given to either the excavation or the bank, and evolved to both the words "dike"/"dyke" and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canal
Canals or artificial waterways are waterways or engineered channels built for drainage management (e.g. flood control and irrigation) or for conveyancing water transport vehicles (e.g. water taxi). They carry free, calm surface flow under atmospheric pressure, and can be thought of as artificial rivers. In most cases, a canal has a series of dams and locks that create reservoirs of low speed current flow. These reservoirs are referred to as ''slack water levels'', often just called ''levels''. A canal can be called a ''navigation canal'' when it parallels a natural river and shares part of the latter's discharges and drainage basin, and leverages its resources by building dams and locks to increase and lengthen its stretches of slack water levels while staying in its valley. A canal can cut across a drainage divide atop a ridge, generally requiring an external water source above the highest elevation. The best-known example of such a canal is the Panama Canal. Many ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
River
A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows into the ground and becomes dry at the end of its course without reaching another body of water. Small rivers can be referred to using names such as Stream#Creek, creek, Stream#Brook, brook, rivulet, and rill. There are no official definitions for the generic term river as applied to Geographical feature, geographic features, although in some countries or communities a stream is defined by its size. Many names for small rivers are specific to geographic location; examples are "run" in some parts of the United States, "Burn (landform), burn" in Scotland and northeast England, and "beck" in northern England. Sometimes a river is defined as being larger than a creek, but not always: the language is vague. Rivers are part of the water cycle. Water generally collects in a river from Precipitation (meteorology), precipitation through a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subway (rail)
Rapid transit or mass rapid transit (MRT), also known as heavy rail or metro, is a type of high-capacity public transport generally found in urban areas. A rapid transit system that primarily or traditionally runs below the surface may be called a subway, tube, or underground. Unlike buses or trams, rapid transit systems are railways (usually electric) that operate on an exclusive right-of-way, which cannot be accessed by pedestrians or other vehicles, and which is often grade-separated in tunnels or on elevated railways. Modern services on rapid transit systems are provided on designated lines between stations typically using electric multiple units on rail tracks, although some systems use guided rubber tires, magnetic levitation (''maglev''), or monorail. The stations typically have high platforms, without steps inside the trains, requiring custom-made trains in order to minimize gaps between train and platform. They are typically integrated with other public transpo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aerial Cable
An aerial cable or air cable is an insulated cable usually containing all conductors required for an electrical distribution system (typically using aerial bundled cables) or a telecommunication line, which is suspended between utility poles or electricity pylons. As aerial cables are completely insulated there is no danger of electric shock when touching them and there is no requirement for mounting them with insulators on pylons and poles. A further advantage is they require less right of way than overhead lines for the same reason. They can be designed as shielded cables for telecommunication purposes. If the cable falls, it may still operate if its insulation is not damaged. As aerial cables are installed on pylons or poles, they may be cheaper to install than underground cables, as no work for digging is required, which can be very expensive in rocky areas. Use Aerial cables are mostly used for telecommunication systems or for power transmissions with voltages bel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telecommunications Equipment
Telecommunications equipment (also telecoms equipment or communications equipment) are hardware which are used for the purposes of telecommunications. Since the 1990s the boundary between telecoms equipment and IT hardware has become blurred as a result of the growth of the internet and its increasing role in the transfer of telecoms data. Types Telecommunications equipment can be broadly broken down into the following categories: *Public switching equipment **Analogue switches **Digital switches ***Voice over IP switches ***Virtual reality (VR) *Transmission equipment **Transmission lines ***Optical fiber ***Local loops **Base transceiver stations **Free-space optical communication ***Laser communication in space **Multiplexers **Communications satellites *Customer premises equipment (CPE) ** Customer office terminal **Private switches **Local area networks (LANs) **Modems **Mobile phones ** Landline telephones **Answering machines **Teleprinters **Fax machines **Pagers ** Router ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
