Telecom Electric Limited began life as a small project within the National Grid plc to determine the feasibility of running suspended optical fibre cables across the pylons of the high voltage power distribution network owned by the company. Three principal techniques were considered:
Optical Ground Wire (OPGW), which replaced the earth wire that runs across the top of the pylons with a new cable that contained a tubular core in which up to 24 optical fibres could be placed. However this option was expensive to implement as it would mean writing off the capital value of the old earth cable many years before it was due to be replaced as part of the normal operation and maintenance cycle. Installation was also very expensive and methods to reduce costs in this area needed to be developed.
Wrapped Fibre (WF), which involved a new technique of taking a variant of underground cable and wrapping it in a spiral fashion around the earth wire. A specially adapted machine was designed for the job to that made installation cost-effective. The challenge for the company however was how to protect the fibres in the cable from damage caused by starlings pecking at the cable sheath, which split open the cable exposing the fibres to water which would affect the optical transmission properties.
All Dielectric Self Supporting (ADSS) Cable, which consisted of non-metallic suspension components and was already used on low voltage power distribution networks in various parts of the world. However, it was found that at 275 kV and 400 kV, the voltages used on the National Grid infrastructure, the electromagnetic fields from the power cables were sufficient to induce microsparks inside the cable that degraded the dielectric materials causing the cable to fail and collapse.
Following various trials, cost-effective installation methods were developed for OPGW and the starling problem was resolved, but no solution was found at that time for the ADSS deterioration problem. These changes made it possible to install a nationwide network within the budget constraints set for the project and approval was given to start.
The other technical issues to resolve was what type of optical transmission equipment to use. A few years before a new standard for optical transmission systems called Synchronous Digital Hierarchy (SDH) had been developed and ratified as a global standard as a replacement for existing Plesiochronous Digital Hierarchy (PDH) equipment. As the Telecom Electric Project started manufacturers had started releasing SDH products onto the market and Russ Taylor, the SDH specialist in the TE team, after researching the UK SDH suppliers, recommended the project implement an all SDH network. This was a bold step at the time, but his research showed that with the right combination of suppliers, it was not only feasible, but would lead to a more efficient network with lower operating costs than the previous PDH products widely used and much more effective than starting with PDH and migrating to SDH over time.
The team reviewed the research material and recommended to the newly appointed CEO David Dey, that Nortel Networks and GPT be selected as suppliers. Nortel Networks were selected to provide the core backbone SDH systems and GPT the edge access systems for SDH-PDH interfacing with the customer. The decision led what was to become Energis Communications Limited to be the first UK operator install an all-SDH network capable of providing a fully synchronous connection to any customer. This unique selling point was a key differentiator in the marketing strategy for the first five years of operation of the business.
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Nepal's telecommunication network has increased over the years significantly, with the number of telephone users reaching 40,789,198 subscribers as on 14 May 2019.
The plesiochronous digital hierarchy (PDH) is a technology used in telecommunications networks to transport large quantities of data over digital transport equipment such as fibre optic and microwave radio systems. The term plesiochronous is derived from Greek plēsios, meaning near, and chronos, time, and refers to the fact that PDH networks run in a state where different parts of the network are nearly, but not quite perfectly, synchronized.
Synchronous optical networking (SONET) and synchronous digital hierarchy (SDH) are standardized protocols that transfer multiple digital bit streams synchronously over optical fiber using lasers or highly coherent light from light-emitting diodes (LEDs). At low transmission rates data can also be transferred via an electrical interface. The method was developed to replace the plesiochronous digital hierarchy (PDH) system for transporting large amounts of telephone calls and data traffic over the same fiber without the problems of synchronization.
Time-division multiplexing (TDM) is a method of transmitting and receiving independent signals over a common signal path by means of synchronized switches at each end of the transmission line so that each signal appears on the line only a fraction of time in an alternating pattern.[<It is a communication process that transmit 2 or more digital signals or analogue signals over a common chanel>] It is used when the bit rate of the transmission medium exceeds that of the signal to be transmitted. This form of signal multiplexing was developed in telecommunications for telegraphy systems in the late 19th century, but found its most common application in digital telephony in the second half of the 20th century.
Packet over SONET/SDH, abbreviated POS, is a communications protocol for transmitting packets in the form of the Point to Point Protocol (PPP) over SDH or SONET, which are both standard protocols for communicating digital information using lasers or light emitting diodes (LEDs) over optical fibre at high line rates. POS is defined by RFC 2615 as PPP over SONET/SDH. PPP is the Point to Point Protocol that was designed as a standard method of communicating over point-to-point links. Since SONET/SDH uses point-to-point circuits, PPP is well suited for use over these links. Scrambling is performed during insertion of the PPP packets into the SONET/SDH frame to solve various security attacks including denial-of-service attacks and the imitation of SONET/SDH alarms. This modification was justified as cost-effective because the scrambling algorithm was already used by the standard used to transport ATM cells over SONET/SDH. However, scrambling can optionally be disabled to allow a node to be compatible with another node that uses the now obsoleted RFC 1619 version of Packet over SONET/SDH which lacks the scrambler.
A utility pole is a column or post used to support overhead power lines and various other public utilities, such as electrical cable, fiber optic cable, and related equipment such as transformers and street lights. It can be referred to as a transmission pole, telephone pole, telecommunication pole, power pole, hydro pole, telegraph pole, or telegraph post, depending on its application. A stobie pole is a multi-purpose pole made of two steel joists held apart by a slab of concrete in the middle, generally found in South Australia.
An overhead power line is a structure used in electric power transmission and distribution to transmit electrical energy across large distances. It consists of one or more conductors suspended by towers or poles. Since most of the insulation is provided by air, overhead power lines are generally the lowest-cost method of power transmission for large quantities of electric energy.
A traction network or traction power network is an electricity grid for the supply of electrified rail networks. The installation of a separate traction network generally is done only if the railway in question uses alternating current (AC) with a frequency lower than that of the national grid, such as in Germany, Austria and Switzerland.
Energis Communications Limited, briefly Telecom Electric, or more usually just Energis, was a 'technology driven communications company' based in the United Kingdom and Ireland. The company was once a constituent of the FTSE 100 Index, but subsequently went into administration, and then became a subsidiary of Cable & Wireless, in turn acquired by Vodafone.
A metropolitan-area Ethernet, Ethernet MAN, or metro Ethernet network is a metropolitan area network (MAN) that is based on Ethernet standards. It is commonly used to connect subscribers to a larger service network or the Internet. Businesses can also use metropolitan-area Ethernet to connect their own offices to each other.
Standard Telephones and Cables Ltd was a British telephone, telegraph, radio, telecommunications, and related equipment R&D manufacturer. During its history, STC invented and developed several groundbreaking new technologies including pulse code modulation (PCM) and optical fibres.
Fiber-optic communication is a method of transmitting information from one place to another by sending pulses of infrared light through an optical fiber. The light forms an electromagnetic carrier wave that is modulated to carry information. Fiber is preferred over electrical cabling when high bandwidth, long distance, or immunity to electromagnetic interference are required. This type of communication can transmit voice, video, and telemetry through local area networks, computer networks, or across long distances.
An optical ground wire is a type of cable that is used in overhead power lines. Such cable combines the functions of grounding and communications. An OPGW cable contains a tubular structure with one or more optical fibers in it, surrounded by layers of steel and aluminum wire. The OPGW cable is run between the tops of high-voltage electricity pylons. The conductive part of the cable serves to bond adjacent towers to earth ground, and shields the high-voltage conductors from lightning strikes. The optical fibers within the cable can be used for high-speed transmission of data, either for the electrical utility's own purposes of protection and control of the transmission line, for the utility's own voice and data communication, or may be leased or sold to third parties to serve as a high-speed fiber interconnection between cities.
Sumitomo Electric Industries, Ltd. (SEI) is a manufacturer of electric wire and optical fiber cables. Its headquarters are in Chūō-ku, Osaka, Japan. The company's shares are listed in the first section of the Tokyo, Nagoya Stock Exchanges, and the Fukuoka Stock Exchange. In the period ending March 2019, the company reported consolidated sales of US$29 billion.
A fiber-optic cable, also known as an optical-fiber cable, is an assembly similar to an electrical cable, but containing one or more optical fibers that are used to carry light. The optical fiber elements are typically individually coated with plastic layers and contained in a protective tube suitable for the environment where the cable will be deployed. Different types of cable are used for different applications, for example, long distance telecommunication, or providing a high-speed data connection between different parts of a building.
TransGrid is the manager and operator of the high voltage electricity transmission network in New South Wales and the Australian Capital Territory, Australia, and is part of the National Electricity Market (NEM). The company's offices are located in Canberra and Sydney.
All-dielectric self-supporting (ADSS) cable is a type of optical fiber cable that is strong enough to support itself between structures without using conductive metal elements. It is used by electrical utility companies as a communications medium, installed along existing overhead transmission lines and often sharing the same support structures as the electrical conductors.
Optical attached cable (OPAC) is a type of fibre optic cable that is installed by being attached to a host conductor along overhead power lines. The attachment system varies and can include wrapping, lashing or clipping the fibre optic cable to the host. Installation is typically performed using a specialised piece of equipment that travels along the host conductor from pole to pole or tower to tower, wrapping, clipping or lashing the fibre optic cable in place. Different manufacturers have different systems and the installation equipment, cable designs and hardware are not interchangeable.
ALBEDO Telecom is a company that designs and manufactures products for the telecom industry including testers, synchronization nodes and networking devices. Typical users are R&D laboratories, Mobile and Telecom operators to verify and install the infrastructures that support any kind of applications based on voice, video and data. It is headquartered in Barcelona, Spain in the European Union.
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