1.
Telecommunication
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Telecommunication is the transmission of signs, signals, messages, writings, images and sounds or intelligence of any nature by wire, radio, optical or other electromagnetic systems. Telecommunication occurs when the exchange of information between communication participants includes the use of technology and it is transmitted either electrically over physical media, such as cables, or via electromagnetic radiation. Such transmission paths are divided into communication channels which afford the advantages of multiplexing. The term is used in its plural form, telecommunications. Early means of communicating over a distance included visual signals, such as beacons, smoke signals, semaphore telegraphs, signal flags, other examples of pre-modern long-distance communication included audio messages such as coded drumbeats, lung-blown horns, and loud whistles. Zworykin, John Logie Baird and Philo Farnsworth, the word telecommunication is a compound of the Greek prefix tele, meaning distant, far off, or afar, and the Latin communicare, meaning to share. Its modern use is adapted from the French, because its use was recorded in 1904 by the French engineer. Communication was first used as an English word in the late 14th century, in the Middle Ages, chains of beacons were commonly used on hilltops as a means of relaying a signal. Beacon chains suffered the drawback that they could pass a single bit of information. One notable instance of their use was during the Spanish Armada, in 1792, Claude Chappe, a French engineer, built the first fixed visual telegraphy system between Lille and Paris. However semaphore suffered from the need for skilled operators and expensive towers at intervals of ten to thirty kilometres, as a result of competition from the electrical telegraph, the last commercial line was abandoned in 1880. Homing pigeons have occasionally used throughout history by different cultures. Pigeon post is thought to have Persians roots and was used by the Romans to aid their military, frontinus said that Julius Caesar used pigeons as messengers in his conquest of Gaul. The Greeks also conveyed the names of the victors at the Olympic Games to various cities using homing pigeons, in the early 19th century, the Dutch government used the system in Java and Sumatra. And in 1849, Paul Julius Reuter started a service to fly stock prices between Aachen and Brussels, a service that operated for a year until the gap in the telegraph link was closed. Sir Charles Wheatstone and Sir William Fothergill Cooke invented the telegraph in 1837. Also, the first commercial electrical telegraph is purported to have constructed by Wheatstone and Cooke. Both inventors viewed their device as an improvement to the electromagnetic telegraph not as a new device, samuel Morse independently developed a version of the electrical telegraph that he unsuccessfully demonstrated on 2 September 1837
2.
Communication channel
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A channel is used to convey an information signal, for example a digital bit stream, from one or several senders to one or several receivers. A channel has a capacity for transmitting information, often measured by its bandwidth in Hz or its data rate in bits per second. Communicating data from one location to another requires some form of pathway or medium and these pathways, called communication channels, use two types of media, cable and broadcast. Cable or wire line media use physical wires of cables to transmit data, twisted-pair wire and coaxial cables are made of copper, and fiber-optic cable is made of glass. In information theory, a channel refers to a theoretical channel model with certain error characteristics, in this more general view, a storage device is also a kind of channel, which can be sent to and received from. Examples of communications include, A connection between initiating and terminating nodes of a circuit. A single path provided by a transmission medium via either physical separation, such as by multipair cable or electrical separation, a path for conveying electrical or electromagnetic signals, usually distinguished from other parallel paths. A storage which can communicate a message over time as well as space The portion of a medium, such as a track or band. A buffer from which messages can be put and got, see Actor model and process calculi for discussion on the use of channels. In a communications system, the physical or logical link that connects a data source to a data sink, a specific radio frequency, pair or band of frequencies, usually named with a letter, number, or codeword, and often allocated by international agreement. Examples, Marine VHF radio uses some 88 channels in the VHF band for two-way FM voice communication, Channel 16, for example, is 156.800 MHz. In the US, seven additional channels, WX1 - WX7, are allocated for weather broadcasts, television channels such as North American TV Channel 2 =55.25 MHz, Channel 13 =211.25 MHz. Each channel is 6 MHz wide, besides these physical channels, television also has virtual channels. Wi-Fi consists of unlicensed channels 1-13 from 2412 MHz to 2484 MHz in 5 MHz steps, the radio channel between an amateur radio repeater and a ham uses two frequencies often 600 kHz apart. For example, a repeater that transmits on 146.94 MHz typically listens for a ham transmitting on 146.34 MHz, all of these communications channels share the property that they transfer information. The information is carried through the channel by a signal, a channel can be modelled physically by trying to calculate the physical processes which modify the transmitted signal. For example, in wireless communications the channel can be modelled by calculating the reflection off every object in the environment, a sequence of random numbers might also be added in to simulate external interference and/or electronic noise in the receiver. Statistical and physical modelling can be combined, for example, in wireless communications the channel is often modelled by a random attenuation of the transmitted signal, followed by additive noise
3.
Communications satellite
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Communications satellites are used for television, telephone, radio, internet, and military applications. There are over 2,000 communications satellites in Earth’s orbit, Wireless communication uses electromagnetic waves to carry signals. These waves require line-of-sight, and are thus obstructed by the curvature of the Earth, the purpose of communications satellites is to relay the signal around the curve of the Earth allowing communication between widely separated points. Communications satellites use a range of radio and microwave frequencies. To avoid signal interference, international organizations have regulations for which frequency ranges or bands certain organizations are allowed to use and this allocation of bands minimizes the risk of signal interference. The concept of the communications satellite was first proposed by Arthur C. Clarke, building on work by Konstantin Tsiolkovsky and on the 1929 work by Herman Potočnik Das Problem der Befahrung des Weltraums — der Raketen-motor, in October 1945 Clarke published an article titled Extraterrestrial Relays in the British magazine Wireless World. The article described the fundamentals behind the deployment of artificial satellites in geostationary orbits for the purpose of relaying radio signals, thus, Arthur C. Clarke is often quoted as being the inventor of the communications satellite and the term Clarke Belt employed as a description of the orbit. Decades later a project named Communication Moon Relay was a project carried out by the United States Navy. Its objective was to develop a secure and reliable method of communication by using the Moon as a passive reflector. The first artificial Earth satellite was Sputnik 1, put into orbit by the Soviet Union on October 4,1957, it was equipped with an on-board radio-transmitter that worked on two frequencies,20.005 and 40.002 MHz. Sputnik 1 was launched as a step in the exploration of space, while incredibly important it was not placed in orbit for the purpose of sending data from one point on earth to another. And it was the first artificial satellite in the leading to todays satellite communications. The first artificial satellite used solely to further advances in communications was a balloon named Echo 1. Echo 1 was the worlds first artificial communications satellite capable of relaying signals to other points on Earth and it soared 1,600 kilometres above the planet after its Aug.12,1960 launch, yet relied on humanitys oldest flight technology — ballooning. Launched by NASA, Echo 1 was a 30-metre aluminized PET film balloon served as a passive reflector for radio communications. The worlds first inflatable satellite — or satelloon, as they were informally known — helped lay the foundation of todays satellite communications, the idea behind a communications satellite is simple, Send data up into space and beam it back down to another spot on the globe. Echo 1 accomplished this by serving as an enormous mirror,10 stories tall
4.
Computer network
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A computer network or data network is a telecommunications network which allows nodes to share resources. In computer networks, networked computing devices exchange data with other using a data link. The connections between nodes are established using either cable media or wireless media, the best-known computer network is the Internet. Network computer devices that originate, route and terminate the data are called network nodes, nodes can include hosts such as personal computers, phones, servers as well as networking hardware. Two such devices can be said to be networked together when one device is able to exchange information with the other device, Computer networks differ in the transmission medium used to carry their signals, communications protocols to organize network traffic, the networks size, topology and organizational intent. In most cases, application-specific communications protocols are layered over other more general communications protocols and this formidable collection of information technology requires skilled network management to keep it all running reliably. The chronology of significant computer-network developments includes, In the late 1950s, in 1960, the commercial airline reservation system semi-automatic business research environment went online with two connected mainframes. Licklider developed a group he called the Intergalactic Computer Network. In 1964, researchers at Dartmouth College developed the Dartmouth Time Sharing System for distributed users of computer systems. The same year, at Massachusetts Institute of Technology, a group supported by General Electric and Bell Labs used a computer to route. Throughout the 1960s, Leonard Kleinrock, Paul Baran, and Donald Davies independently developed network systems that used packets to transfer information between computers over a network, in 1965, Thomas Marill and Lawrence G. Roberts created the first wide area network. This was an precursor to the ARPANET, of which Roberts became program manager. Also in 1965, Western Electric introduced the first widely used telephone switch that implemented true computer control, in 1972, commercial services using X.25 were deployed, and later used as an underlying infrastructure for expanding TCP/IP networks. In July 1976, Robert Metcalfe and David Boggs published their paper Ethernet, Distributed Packet Switching for Local Computer Networks, in 1979, Robert Metcalfe pursued making Ethernet an open standard. In 1976, John Murphy of Datapoint Corporation created ARCNET, a network first used to share storage devices. In 1995, the transmission speed capacity for Ethernet increased from 10 Mbit/s to 100 Mbit/s, by 1998, Ethernet supported transmission speeds of a Gigabit. Subsequently, higher speeds of up to 100 Gbit/s were added, the ability of Ethernet to scale easily is a contributing factor to its continued use. Providing access to information on shared storage devices is an important feature of many networks, a network allows sharing of files, data, and other types of information giving authorized users the ability to access information stored on other computers on the network
5.
Optical fiber
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An optical fiber or optical fibre is a flexible, transparent fiber made by drawing glass or plastic to a diameter slightly thicker than that of a human hair. Fibers are also used for illumination, and are wrapped in bundles so that they may be used to carry images, thus allowing viewing in confined spaces, as in the case of a fiberscope. Specially designed fibers are used for a variety of other applications, some of them being fiber optic sensors. Optical fibers typically include a transparent core surrounded by a transparent cladding material with an index of refraction. Light is kept in the core by the phenomenon of internal reflection which causes the fiber to act as a waveguide. Fibers that support many propagation paths or transverse modes are called multi-mode fibers, multi-mode fibers generally have a wider core diameter and are used for short-distance communication links and for applications where high power must be transmitted. Single-mode fibers are used for most communication links longer than 1,000 meters, being able to join optical fibers with low loss is important in fiber optic communication. This is more complex than joining electrical wire or cable and involves careful cleaving of the fibers, precise alignment of the cores. For applications that demand a permanent connection a fusion splice is common, in this technique, an electric arc is used to melt the ends of the fibers together. Another common technique is a splice, where the ends of the fibers are held in contact by mechanical force. Temporary or semi-permanent connections are made by means of specialized optical fiber connectors, the field of applied science and engineering concerned with the design and application of optical fibers is known as fiber optics. The term was coined by Indian physicist Narinder Singh Kapany who is acknowledged as the father of fiber optics. Guiding of light by refraction, the principle that makes fiber optics possible, was first demonstrated by Daniel Colladon, John Tyndall included a demonstration of it in his public lectures in London,12 years later. When the ray passes from water to air it is bent from the perpendicular. If the angle which the ray in water encloses with the perpendicular to the surface be greater than 48 degrees, the angle which marks the limit where total reflection begins is called the limiting angle of the medium. For water this angle is 48°27′, for flint glass it is 38°41′, unpigmented human hairs have also been shown to act as an optical fiber. Practical applications, such as close internal illumination during dentistry, appeared early in the twentieth century, image transmission through tubes was demonstrated independently by the radio experimenter Clarence Hansell and the television pioneer John Logie Baird in the 1920s. The principle was first used for medical examinations by Heinrich Lamm in the following decade
6.
Point-to-point (telecommunications)
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In telecommunications, a point-to-point connection refers to a communications connection between two nodes or endpoints. An example is a call, in which one telephone is connected with one other. This is contrasted with a point-to-multipoint or broadcast connection, in which many nodes can receive information transmitted by one node, other examples of point-to-point communications links are leased lines, microwave relay links, and two way radio. Point-to-point is sometimes abbreviated as P2P and this usage of P2P is distinct from P2P referring to peer-to-peer for file sharing networks. A traditional point-to-point data link is a medium with exactly two endpoints and no data or packet formatting. The host computers at either end had to take responsibility for formatting the data transmitted between them. The connection between the computer and the medium was generally implemented through an RS-232 or similar interface. Computers in close proximity may be connected by wires directly between their interface cards, when connected at a distance, each endpoint would be fitted with a modem to convert analog telecommunications signals into a digital data stream. When the connection used a telecommunications provider, the connections were called a dedicated, leased, the ARPANET used leased lines to provide point-to-point data links between its packet-switching nodes, which were called Interface Message Processors. In, the term point-to-point telecommunications relates to fixed wireless communications for Internet or voice over IP via radio frequencies in the multi-gigahertz range. The Telecommunications Industry Associations engineering committees develop U. S. standards for point-to-point communications, online tools help users find if they have such line of sight. The telecommunications signal is typically bi-directional, either time division multiple access or channelized, in hubs and switches, a hub provides a point-to-multipoint circuit which divides the total bandwidth supplied by the hub among each connected client node. Within many switched telecommunications systems, it is possible to establish a permanent circuit, one example might be a telephone in the lobby of a public building, which is programmed to ring only the number of a telephone dispatcher. Nailing down a switched connection saves the cost of running a circuit between the two points. The resources in such a connection can be released when no longer needed, for example, a television circuit from a parade route back to the studio
7.
Ethernet
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Ethernet /ˈiːθərnɛt/ is a family of computer networking technologies commonly used in local area networks, metropolitan area networks and wide area networks. It was commercially introduced in 1980 and first standardized in 1983 as IEEE802.3, over time, Ethernet has largely replaced competing wired LAN technologies such as token ring, FDDI and ARCNET. The original 10BASE5 Ethernet uses coaxial cable as a medium, while the newer Ethernet variants use twisted pair. Over the course of its history, Ethernet data transfer rates have increased from the original 2.94 megabits per second to the latest 100 gigabits per second. The Ethernet standards comprise several wiring and signaling variants of the OSI physical layer in use with Ethernet, systems communicating over Ethernet divide a stream of data into shorter pieces called frames. As per the OSI model, Ethernet provides services up to, since its commercial release, Ethernet has retained a good degree of backward compatibility. Features such as the 48-bit MAC address and Ethernet frame format have influenced other networking protocols, the primary alternative for some uses of contemporary LANs is Wi-Fi, a wireless protocol standardized as IEEE802.11. Ethernet was developed at Xerox PARC between 1973 and 1974 and it was inspired by ALOHAnet, which Robert Metcalfe had studied as part of his PhD dissertation. In 1975, Xerox filed a patent application listing Metcalfe, David Boggs, Chuck Thacker, in 1976, after the system was deployed at PARC, Metcalfe and Boggs published a seminal paper. Metcalfe left Xerox in June 1979 to form 3Com and he convinced Digital Equipment Corporation, Intel, and Xerox to work together to promote Ethernet as a standard. The so-called DIX standard, for Digital/Intel/Xerox, specified 10 Mbit/s Ethernet, with 48-bit destination and source addresses and it was published on September 30,1980 as The Ethernet, A Local Area Network. Data Link Layer and Physical Layer Specifications, version 2 was published in November,1982 and defines what has become known as Ethernet II. Formal standardization efforts proceeded at the time and resulted in the publication of IEEE802.3 on June 23,1983. Ethernet initially competed with two largely proprietary systems, Token Ring and Token Bus, in the process, 3Com became a major company. 3Com shipped its first 10 Mbit/s Ethernet 3C100 NIC in March 1981, an Ethernet adapter card for the IBM PC was released in 1982, and, by 1985, 3Com had sold 100,000. Parallel port based Ethernet adapters were produced for a time, with drivers for DOS, by the early 1990s, Ethernet became so prevalent that it was a must-have feature for modern computers, and Ethernet ports began to appear on some PCs and most workstations. This process was sped up with the introduction of 10BASE-T and its relatively small modular connector. Since then, Ethernet technology has evolved to meet new bandwidth, in addition to computers, Ethernet is now used to interconnect appliances and other personal devices
8.
Asynchronous Transfer Mode
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ATM was developed to meet the needs of the Broadband Integrated Services Digital Network, as defined in the late 1980s, and designed to unify telecommunication and computer networks. It was designed for a network that must handle both traditional high-throughput data traffic, and real-time, low-latency content such as voice and video. The reference model for ATM approximately maps to the three lowest layers of the ISO-OSI reference model, network layer, data link layer, and physical layer. ATM is a protocol used over the SONET/SDH backbone of the public switched telephone network and Integrated Services Digital Network. This differs from approaches such as the Internet Protocol or Ethernet that use variable sized packets, ATM uses a connection-oriented model in which a virtual circuit must be established between two endpoints before the actual data exchange begins. ATM eventually became dominated by Internet Protocol only technology, in the ISO-OSI reference model data link layer, the basic transfer units are generically called frames. In ATM these frames are of a length and specifically called cells. Under normal queuing conditions the cells might experience maximum queuing delays, to avoid this issue, all ATM packets, or cells, are the same small size. In addition, the cell structure means that ATM can be readily switched by hardware without the inherent delays introduced by software switched and routed frames. Thus, the designers of ATM utilized small data cells to reduce jitter in the multiplexing of data streams.544 to 45 Mbit/s in the USA, at this rate, a typical full-length 1500 byte data packet would take 77.42 µs to transmit. In a lower-speed link, such as a 1.544 Mbit/s T1 line, a queuing delay induced by several such data packets might exceed the figure of 7.8 ms several times over, in addition to any packet generation delay in the shorter speech packet. This was clearly unacceptable for speech traffic, which needs to have low jitter in the stream being fed into the codec if it is to produce good-quality sound. This allows smoothing out the jitter, but the delay introduced by passage through the buffer would require echo cancellers even in local networks, also, it would have increased the delay across the channel, and conversation is difficult over high-delay channels. Build a system that can provide low jitter to traffic that needs it. Operate on a 1,1 user basis, the design of ATM aimed for a low-jitter network interface. However, cells were introduced into the design to provide short queuing delays while continuing to support datagram traffic, ATM broke up all packets, data, and voice streams into 48-byte chunks, adding a 5-byte routing header to each one so that they could be reassembled later. The choice of 48 bytes was political rather than technical, most of the European parties eventually came around to the arguments made by the Americans, but France and a few others held out for a shorter cell length. With 32 bytes, France would have been able to implement an ATM-based voice network with calls from one end of France to the other requiring no echo cancellation,48 bytes was chosen as a compromise between the two sides
9.
Frame Relay
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Frame Relay is a standardized wide area network technology that specifies the physical and data link layers of digital telecommunications channels using a packet switching methodology. Originally designed for transport across Integrated Services Digital Network infrastructure, it may be used today in the context of other network interfaces. Network providers commonly implement Frame Relay for voice and data as a technique used between local area networks over a wide area network. Each end-user gets a line to a Frame Relay node. The Frame Relay network handles the transmission over a frequently changing path transparent to all end-user extensively used WAN protocols and it is less expensive than leased lines and that is one reason for its popularity. The extreme simplicity of configuring user equipment in a Frame Relay network offers another reason for Frame Relays popularity. With the advent of Ethernet over fiber optics, MPLS, VPN and dedicated broadband services such as cable modem and DSL, however many rural areas remain lacking DSL and cable modem services. In such cases, the least expensive type of non-dial-up connection remains a 64-kbit/s Frame Relay line, thus a retail chain, for instance, may use Frame Relay for connecting rural stores into their corporate WAN. Frame Relay puts data in units called frames and leaves any necessary error-correction up to the end-points. This speeds up overall data transmission, an enterprise can select a level of service quality, prioritizing some frames and making others less important. Frame Relay can run on fractional T-1 or full T-carrier system carriers.520 Mbit/s to 622.080 Mbit/s, Frame Relay has its technical base in the older X.25 packet-switching technology, designed for transmitting data on analog voice lines. When a Frame Relay network detects an error in a frame, the end points have the responsibility for detecting and retransmitting dropped frames. Frame Relay often serves to connect local area networks with major backbones, as well as on public wide-area networks and it requires a dedicated connection during the transmission period. Frame Relay does not provide a path for voice or video transmission. However, under circumstances, voice and video transmission do use Frame Relay. Frame Relay originated as an extension of integrated services digital network and its designers aimed to enable a packet-switched network to transport over circuit-switched technology. The technology has become a stand-alone and cost-effective means of creating a WAN, Frame Relay switches create virtual circuits to connect remote LANs to a WAN. The Frame Relay network exists between a LAN border device, usually a router, and the carrier switch, the technology used by the carrier to transport data between the switches is variable and may differ among carriers
10.
X.25
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X.25 is an ITU-T standard protocol suite for packet switched wide area network communication. An X.25 WAN consists of packet-switching exchange nodes as the networking hardware, X.25 is a family of protocols that was popular during the 1980s with telecommunications companies and in financial transaction systems such as automated teller machines. X.25 was originally defined by the International Telegraph and Telephone Consultative Committee in a series of drafts and finalized in a publication known as The Orange Book in 1976. While X.25 has, to an extent, been replaced by less complex protocols, especially the Internet protocol. X.25 is one of the oldest packet-switched services available and it was developed before the OSI Reference Model. The protocol suite is designed as three conceptual layers, which correspond closely to the three layers of the seven-layer OSI model. It also supports functionality not found in the OSI network layer, X.25 was developed in the ITU-T Study Group VII based upon a number of emerging data network projects. Various updates and additions were worked into the standard, eventually recorded in the ITU series of books describing the telecommunication systems. These books were published every year with different-colored covers. The X.25 specification is only part of the set of X-Series specifications on public data networks. The public data network was the name given to the international collection of X.25 providers. Their combined network had large global coverage during the 1980s and into the 1990s, publicly accessible X.25 networks were set up in most countries during the 1970s and 1980s, to lower the cost of accessing various online services. Beginning in the early 1990s, in North America, use of X.25 networks started to be replaced by Frame Relay, most systems that required X.25 now use TCP/IP, however it is possible to transport X.25 over TCP/IP when necessary. X.25 networks are still in use throughout the world, a variant called AX.25 is also used widely by amateur packet radio. Racal Paknet, now known as Widanet, is still in operation in many regions of the world, running on an X.25 protocol base. Additionally X.25 is still under heavy use in the business even though a transition to modern protocols like X.400 is without option as X.25 hardware becomes increasingly rare. As recently as March 2006, the United States National Airspace Data Interchange Network has used X.25 to interconnect remote airfields with Air Route Traffic Control Centers, france was one of the last remaining countries where commercial end-user service based on X.25 operated. Known as Minitel it was based on Videotex, itself running on X.25, as planned, service was terminated 30 June 2012
11.
Internet Protocol
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The Internet Protocol is the principal communications protocol in the Internet protocol suite for relaying datagrams across network boundaries. Its routing function enables internetworking, and essentially establishes the Internet, IP has the task of delivering packets from the source host to the destination host solely based on the IP addresses in the packet headers. For this purpose, IP defines packet structures that encapsulate the data to be delivered and it also defines addressing methods that are used to label the datagram with source and destination information. The Internet protocol suite is often referred to as TCP/IP. The first major version of IP, Internet Protocol Version 4, is the dominant protocol of the Internet and its successor is Internet Protocol Version 6. The Internet Protocol is responsible for addressing hosts and for routing datagrams from a source host to a destination host across one or more IP networks. For this purpose, the Internet Protocol defines the format of packets, each datagram has two components, a header and a payload. The IP header is tagged with the source IP address, the destination IP address, the payload is the data that is transported. This method of nesting the data payload in a packet with a header is called encapsulation, IP addressing entails the assignment of IP addresses and associated parameters to host interfaces. The address space is divided into networks and subnetworks, involving the designation of network or routing prefixes, IP routing is performed by all hosts, as well as routers, whose main function is to transport packets across network boundaries. Routers communicate with one another via specially designed routing protocols, either interior gateway protocols or exterior gateway protocols, IP routing is also common in local networks. For example, many Ethernet switches support IP multicast operations and these switches use IP addresses and Internet Group Management Protocol to control multicast routing but use MAC addresses for the actual routing. The versions currently relevant are IPv4 and IPv6, in May 1974, the Institute of Electrical and Electronic Engineers published a paper entitled A Protocol for Packet Network Intercommunication. The papers authors, Vint Cerf and Bob Kahn, described a protocol for sharing resources using packet switching among network nodes. A central control component of this model was the Transmission Control Program that incorporated both connection-oriented links and datagram services between hosts, the model became known as the Department of Defense Internet Model and Internet protocol suite, and informally as TCP/IP. IP versions 0 to 3 were experimental versions, used between 1977 and 1979, IEN26, dated February 1978 describes a version of the IP header that uses a 1-bit version field. IEN28, dated February 1978 describes IPv2, IEN41, dated June 1978 describes the first protocol to be called IPv4. The IP header is different from the modern IPv4 header, IEN44, dated June 1978 describes another version of IPv4, also with a header different from the modern IPv4 header
12.
Point-to-multipoint communication
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Point-to-multipoint is often abbreviated as P2MP, PTMP, or PMP. Point-to-multipoint telecommunications is most typically used in wireless Internet and IP telephony via gigahertz radio frequencies, P2MP systems have been designed both as single and bi-directional systems. A central antenna or antenna array broadcasts to several receiving antennas, Point to Multipoint is the most popular approach for wireless communications that have a large number of nodes, end destinations or end users. Point to Multipoint generally assumes there is a central Base Station to which remote Subscriber Units or Customer Premises Equipment, connections between the Base Station and Subscriber Units can be either Line of Sight or for lower-frequency radio systems Non-Line-of-Sight where link budgets permit. Generally, lower frequencies can offer non-Line-of Sight connections, various software planning tools can be used to determine feasibility of potential connections using topographic data as well as link budget simulation. Often the point to multipoint links are installed to reduce the cost of infrastructure and increase the number of CPEs, Point to Multipoint wireless networks employing directional antennas are affected by the hidden node problem in case they employ a CSMA/CA medium access control protocol. The negative impact of the hidden node problem can be mitigated using a TDMA based protocol or a polling protocol rather than the CSMA/CA protocol, the telecommunications signal in a Point to Multipoint system is typically bi-directional, either time division multiple access or channelized. Systems using Frequency Division Duplexing offer full duplex connections between base station and remote sites, and Time Division Duplex systems offer half duplex connections, Point to Multipoint systems can be implemented in Licensed, Semi-licensed or Unlicensed frequency bands depending on the specific application. The Base Station may have a single Omnidirectional antenna or multiple Sector Antennas which is used to increase both range and capacity. All-to-all communication Multipoint microwave distribution system Point-to-point Wireless Communications Wireless Access Point List of emerging technologies Backhaul
13.
Radiocommunication service
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This article incorporates information from the equivalent article on the German Wikipedia. Radiocommunication is sub-divided into space and terrestrial radiocommunication, terrestrial radiocommunication is defined as “any radiocommunication other than space radiocommunication or radio astronomy”. Some services are a sub-set of another service, for example, the land mobile service can be thought of as a branch of the mobile service which encompasses the land, maritime and aeronautical mobile services. For many terrestrial radiocommunication communication services, there is a parallel space radiocommunication service e. g. the broadcasting service, further sub-sets of some of these internationally defined services are often created at the national level. Many of these definitions are based upon the nature of the service being provided rather than the concept of a radiocommunication service. In other words, the term “service” can be used in two different ways. Note that the radio service is not a radiocommunication service
14.
Ground station
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For stations controlling unmanned aerial vehicles, see Ground control station. Ground stations may be located either on the surface of the Earth, Earth stations communicate with spacecraft by transmitting and receiving radio waves in the super high frequency or extremely high frequency bands. When a ground station successfully transmits radio waves to a spacecraft, a principal telecommunications device of the ground station is the parabolic antenna. Ground stations may have either a fixed or itinerant position, article 1 § III of the ITU Radio Regulations describes various types of stationary and mobile ground stations, and their interrelationships. Specialized satellite earth stations are used to telecommunicate with satellites—chiefly communications satellites, other ground stations communicate with manned space stations or unmanned space probes. A ground station that primarily receives telemetry data, or that follows a satellite not in geostationary orbit, is called a tracking station, when a satellite is within a ground stations line of sight, the station is said to have a view of the satellite. It is possible for a satellite to communicate with more than one station at a time. A pair of stations are said to have a satellite in mutual view when the stations share simultaneous, unobstructed. Teleports may provide various broadcasting services among other functions, such as uploading computer programs or issuing commands over an uplink to a satellite. In May 1984, the Dallas/Fort Worth Teleport became the first American teleport to commence operation, the Telecommunications Industry Association also acknowledges this definition. The ITU Radiocommunication Sector, a division of the International Telecommunication Union, from 1927 to 1932, standards and regulations now governed by the ITU-R were administered by the International Consultative Committee for Radio. Eutelsat publishes similar standards and requirements, such as the Eutelsat Earth Station Standards, uplinkStation. com, a corporate directory of commercial teleports, satellite television operators, et al. World Teleport Association Accessed on 22 April 2009
15.
High-altitude platform station
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High-altitude platform station is – according to Article 1. Each station shall be classified by the service in which it operates permanently or temporarily, see also A HAP can be a manned or unmanned airplane, a balloon, or an airship. All require electrical power to themselves and their payload functional. While current HAPS are powered by batteries or engines, mission time is limited by the need for recharging/refueling, therefore, alternative means are being considered for the future. Solar cells are one of the best options currently being used under trial for HAPS, whether an airship or an aeroplane, a major challenge is the ability of the HAP to maintain stationkeeping in the face of winds. An operating altitude between 17 and 22 km is chosen because in most regions of the world this represents a layer of relatively mild wind, although the wind profile may vary considerably with latitude and with season, a form similar to that shown will usually obtain. This altitude is also above commercial air-traffic heights, which would prove a potentially prohibitive constraint. Since HAPS operate at lower altitudes than satellites, it is possible to cover a small region much more effectively. Lower altitude also means much lower telecommunications link budget and smaller round-trip delay compared to satellites, furthermore, deploying a satellite requires significant time and monetary resources, in terms of development and launch. HAPS, on the hand, are comparatively less expensive and are rapidly deployable. Another major difference is that a satellite, once launched, cannot be landed for maintenance, one of latest uses of HAPS has been for radiocommunication service. Research on HAPS is being carried largely in Europe, where scientists are considering them as a platform to deliver high-speed connectivity to users. High-altitude airships can improve the ability to communicate in remote areas such as those in Afghanistan. One of the best examples of a platform used for surveillance. It has a ceiling of 20 km and can stay in the air for continuous 36 hours. It carries a highly sophisticated sensor system including radar, optical and it is powered by a turbofan engine and is able to deliver digital sensor data in realtime to a ground station. Perhaps the most common use of platforms is for environment/weather monitoring. Numerous experiments are conducted through high-altitude balloons mounted with scientific equipment, recently, NASA in partnership with The National Oceanic and Atmospheric Administration, has started using Global Hawk UAV to study Earths atmosphere
16.
GSM
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As of 2014 it has become the de facto global standard for mobile communications – with over 90% market share, operating in over 219 countries and territories. This expanded over time to include communications, first by circuit-switched transport, then by packet data transport via GPRS. Subsequently, the 3GPP developed third-generation UMTS standards followed by fourth-generation LTE Advanced standards, GSM is a trademark owned by the GSM Association. It may also refer to the most common voice codec used, the decision to develop a continental standard eventually resulted in a unified, open, standard-based network which was larger than that in the United States. In February 1987 Europe produced the very first agreed GSM Technical Specification, the MoU drew-in mobile operators from across Europe to pledge to invest in new GSM networks to an ambitious common date. In 1989, the Groupe Spécial Mobile committee was transferred from CEPT to the European Telecommunications Standards Institute, in parallel, France and Germany signed a joint development agreement in 1984 and were joined by Italy and the UK in 1986. In 1986 the European Commission proposed reserving the 900 MHz spectrum band for GSM, the former Finnish prime minister Harri Holkeri made the worlds first GSM call on July 1,1991, calling Kaarina Suonio using a network built by Telenokia and Siemens and operated by Radiolinja. In the following year,1992, saw the sending of the first short messaging service message, work began in 1991 to expand the GSM standard to the 1800 MHz frequency band and the first 1800 MHz network became operational in the UK by 1993 called and DCS1800. Also that year, Telecom Australia became the first network operator to deploy a GSM network outside Europe and the first practical hand-held GSM mobile phone became available. In 1995, fax, data and SMS messaging services were launched commercially, in the same year, the GSM Association formed. Pre-paid GSM SIM cards were launched in 1996 and worldwide GSM subscribers passed 100 million in 1998, in 2000 the first commercial GPRS services were launched and the first GPRS-compatible handsets became available for sale. In 2001 the first UMTS network was launched, a 3G technology that is not part of GSM, worldwide GSM subscribers exceeded 500 million. In 2002 the first Multimedia Messaging Service were introduced and the first GSM network in the 800 MHz frequency band became operational, EDGE services first became operational in a network in 2003 and the number of worldwide GSM subscribers exceeded 1 billion in 2004. By 2005, GSM networks accounted for more than 75% of the cellular network market. In 2005 the first HSDPA-capable network also became operational, the first HSUPA network launched in 2007. Worldwide GSM subscribers exceeded three billion in 2008, GSM is a second-generation standard employing time-division multiple-Access spectrum-sharing, issued by the European Telecommunications Standards Institute. GSM, for the first time, set a standard for Europe for wireless networks. It was also adopted by many countries outside Europe and this allowed subscribers to use other GSM networks that have roaming agreements with each other
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Base transceiver station
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A base transceiver station is a piece of equipment that facilitates wireless communication between user equipment and a network. UEs are devices like mobile phones, WLL phones, computers with wireless Internet connectivity, the network can be that of any of the wireless communication technologies like GSM, CDMA, wireless local loop, Wi-Fi, WiMAX or other wide area network technology. BTS is also referred to as the base station, node B or, simply. For discussion of the LTE standard the abbreviation eNB for evolved node B is widely used, though the term BTS can be applicable to any of the wireless communication standards, it is generally associated with mobile communication technologies like GSM and CDMA. In this regard, a BTS forms part of the base station subsystem developments for system management, typically a BTS will have several transceivers which allow it to serve several different frequencies and different sectors of the cell. A BTS is controlled by a parent base station controller via the station control function. The BCF is implemented as a unit or even incorporated in a TRX in compact base stations. The BCF provides an operations and maintenance connection to the management system. The basic structure and functions of the BTS remains the same regardless of the wireless technologies, a BTS is usually composed of, Transceiver Quite widely referred to as the driver receiver, DRX are either in form of single, double or a composite double radio unit. It basically does transmission and reception of signals and it also does sending and reception of signals to and from higher network entities. Power amplifier Amplifies the signal from DRX for transmission through antenna, combiner Combines feeds from several DRXs so that they could be sent out through a single antenna. Allows for a reduction in the number of antenna used, multiplexer For separating sending and receiving signals to/from antenna. Does sending and receiving signals through the same antenna ports, antenna This is the structure that the BTS lies underneath, it can be installed as it is or disguised in some way. Alarm extension system Collects working status alarms of various units in the BTS and extends them to operations, control function Controls and manages the various units of BTS, including any software. On-the-spot configurations, status changes, software upgrades, etc. are done through the control function, baseband receiver unit Frequency hopping, signal DSP. Diversity techniques To improve the quality of the signal, often two receiving antennas are used, placed at a distance equal to an odd multiple of a quarter of the corresponding wavelength. For 900 MHz, this wavelength is 30 cm and this technique, known as antenna diversity or space diversity, avoids interruption caused by path fading. The antennas can be spaced horizontally or vertically, horizontal spacing requires more complex installation, but brings better performance
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Base station subsystem
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Typically a BTS for anything other than a picocell will have several transceivers which allow it to serve several different frequencies and different sectors of the cell. A BTS is controlled by a parent BSC via the station control function. The BCF is implemented as a unit or even incorporated in a TRX in compact base stations. The BCF provides an operations and maintenance connection to the management system. The functions of a BTS vary depending on the technology used. There are vendors which build their BTSs so the information is preprocessed, target cell lists are generated, the advantage in this case is less load on the expensive Abis interface. This modulation is a kind of continuous-phase frequency shift keying, antenna combiners are implemented to use the same antenna for several TRXs, the more TRXs are combined the greater the combiner loss will be. Up to 8,1 combiners are found in micro and pico cells only, frequency hopping is often used to increase overall BTS performance, this involves the rapid switching of voice traffic between TRXs in a sector. A hopping sequence is followed by the TRXs and handsets using the sector, several hopping sequences are available, and the sequence in use for a particular cell is continually broadcast by that cell so that it is known to the handsets. A TRX transmits and receives according to the GSM standards, which specify eight TDMA timeslots per radio frequency, a TRX may lose some of this capacity as some information is required to be broadcast to handsets in the area that the BTS serves. This information allows the handsets to identify the network and gain access to it and this signalling makes use of a channel known as the Broadcast Control Channel. By using directional antennas on a station, each pointing in different directions. Typically these directional antennas have a beamwidth of 65 to 85 degrees and this increases the traffic capacity of the base station whilst not greatly increasing the interference caused to neighboring cells. Typically two antennas are used per sector, at spacing of ten or more wavelengths apart and this allows the operator to overcome the effects of fading due to physical phenomena such as multipath reception. Some amplification of the signal as it leaves the antenna is often used to preserve the balance between uplink and downlink signal. The base station controller provides, classically, the intelligence behind the BTSs, typically a BSC has tens or even hundreds of BTSs under its control. The BSC handles allocation of channels, receives measurements from the mobile phones. A key function of the BSC is to act as a concentrator where many different low capacity connections to BTSs become reduced to a number of connections towards the mobile switching center
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Data circuit-terminating equipment
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A data circuit-terminating equipment is a device that sits between the data terminal equipment and a data transmission circuit. It is also called data communication equipment and data carrier equipment, usually, the DTE device is the terminal, and the DCE is a modem. In a data station, the DCE performs functions such as conversion, coding. Interfacing equipment may be required to couple the data terminal equipment into a circuit or channel. Although the terms are most commonly used with RS-232, several data communication standards define different types of interfaces between a DCE and a DTE, the DCE is a device that communicates with a DTE device in these standards. D-sub connectors follow another rule for pin assignment, DTE devices usually transmit on pin connector number 2 and receive on pin connector number 3. DCE devices are just the opposite, pin connector number 2 receives, Data Terminating Equipment or Data Circuit-Terminating Equipment speeds, IBM
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Backbone network
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A backbone is a part of computer network that interconnects various pieces of network, providing a path for the exchange of information between different LANs or subnetworks. A backbone can tie together diverse networks in the building, in different buildings in a campus environment. Normally, the capacity is greater than the networks connected to it. The pieces of the connections that bring these departments together is often mentioned as network backbone. Network congestion is often taken into consideration while designing backbones, one example of a backbone network is the Internet backbone. This kind of topology allows for expansion and limited capital outlay for growth. Distributed backbones, in all practicality, are in use by all large-scale networks, applications in enterprise-wide scenarios confined to a single building are also practical, as certain connectivity devices can be assigned to certain floors or departments. Each floor or department possesses a LAN and a closet with that workgroups main hub or router connected to a bus-style network using backbone cabling. Another advantage of using a distributed backbone is the ability for network administrator to segregate workgroups for ease of management, there is the possibility of single points of failure, referring to connectivity devices high in the series hierarchy. The distributed backbone must be designed to separate network traffic circulating on each individual LAN from the network traffic by using access devices such as routers. A collapsed backbone is a type of network architecture. The traditional backbone network goes over the globe to provide interconnectivity to the remote hubs, in most cases, the backbones are the links while the switching or routing functions are done by the equipment at each hub. In the case of a collapsed or inverted backbone, each hub provides a back to a central location to be connected to a backbone-in-a-box. That box can be a switch or a router, the topology and architecture of a collapsed backbone is a star or a rooted tree. However, the drawback of the backbone is that if the box housing the backbone is down or there are reachability problem to the central location. These problems can be minimized by having redundant backbone boxes as well as having secondary/backup backbone locations, there are a few different types of backbones that are used for an enterprise-wide network. When organizations are looking for a strong and trustworthy backbone they should choose a parallel backbone. This backbone is a variation of a backbone in that it uses a central node
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Upstream (networking)
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In computer networking, upstream refers to the direction in which data can be transferred from the client to the server. This differs greatly from downstream not only in theory and usage, upstream speeds are also important to users of peer-to-peer software. ADSL and cable modems are asymmetric, with the data rate much lower than that of its downstream. Symmetric connections such as Symmetric Digital Subscriber Line and T1, however, offer identical upstream and downstream rates. If a node A on the Internet is closer to the Internet backbone than a node B, then A is said to be upstream of B or conversely, related to this is the idea of upstream providers. An upstream provider is usually a large ISP that provides Internet access to a local ISP, hence, the word upstream also refers to the data connection between two ISPs
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Downstream (networking)
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In a telecommunications network or computer network, downstream refers to data sent from a network service provider to a customer. Although the best dial-up modems are called 56 kbit/s modems, downstream speeds can be limited to a few tens of kilobits per second with even lower upstream speeds, asymmetric digital subscriber line and cable modems, two popular Internet access technologies, greatly improved downstream speeds reaching several Mbit/s. Mobile broadband and satellite Internet access providers also often have lower speeds than downstream. One process sending data primarily in the direction is downloading. However, the download speed depends on the downstream speed of the user, the upstream speed of the server. In the client–server model, downstream can refer to the direction from the server to the client
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Base station
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Base station is – according to article 1.71 of the International Telecommunication Union´s ITU Radio Regulations – defined as A land station in the land mobile service. In mobile telephony it provides the connection between mobile phones and the telephone network. In a computer network it is a transceiver acting as a router for computers in the network, in the context of external land surveying, a base station is a GPS receiver at an accurately-known fixed location which is used to derive correction information for nearby portable GPS receivers. It typically consists of a transmitter and wireless router. The base station is one end of a communications link, the other end is a movable vehicle-mounted radio or walkie-talkie. Examples of base station uses in two-way radio include the dispatch of tow trucks, professional base station radios are often one channel. In lightly used stations, a multi-channel unit may be employed. In heavily used systems, the capability for additional channels, where needed, is accomplished by installing an additional station for each channel. Each base station appears as a channel on the dispatch center control console. In a properly designed dispatch center with several members, this allows each dispatcher to communicate simultaneously, independently of one another. For example, a taxi company dispatch center may have one station on a high-rise building in Boston. Each taxi dispatcher could communicate with taxis in either Boston or Providence by selecting the respective base station on his or her console, in dispatching centers it is common for eight or more radio base stations to be connected to a single dispatching console. Dispatching personnel can tell which channel a message is being received on by a combination of local protocol, unit identifiers, volume settings, a typical console has two speakers identified as select and unselect. Audio from a selected channel is routed to the select speaker. Each channel has a light which flashes when someone talks on the associated channel. Base stations can be controlled or remote controlled. Local controlled base stations are operated by front panel controls on the base station cabinet, remote control base stations can be operated over tone- or DC-remote circuits. The dispatch point console and remote base station are connected by leased private line telephone circuits, the consoles multiplex transmit commands onto remote control circuits
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Backhaul (telecommunications)
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In contracts pertaining to such networks, backhaul is the obligation to carry packets to and from that global network. A non-technical business definition of backhaul is the commercial wholesale bandwidth provider who offers quality of service guarantees to the retailer, sometimes middle mile networks exist between the customers own LAN and those exchanges. These serve retail networks which in turn connect buildings and bill customers directly, see national broadband plans from around the world, many of which were motivated by the perceived need to break the monopoly of incumbent commercial providers. The US plan for instance specifies that all community anchor institutions should be connected by fiber optics before the end of 2020. Other examples include, Connecting wireless base stations to the base station controllers. Connecting DSLAMs to the nearest ATM or Ethernet aggregation node, Connecting a large companys site to a metro Ethernet network. Connecting a submarine cable system landing point with the main terrestrial telecommunications network of the country that the cable serves. The choice of backhaul technology must take account of such parameters as capacity, cost, reach, generally, backhaul solutions can largely be categorised into wired or wireless. Wired is usually an expensive solution and often impossible to deploy in remote areas. As data rates increase, the range of network coverage is reduced. Mesh networks are unique enablers that can reduce this cost due to their flexible architecture, with mesh networking, access points are connected wirelessly and exchange data frames with each other to forward to/from a gateway point. Since a mesh requires no costly cable constructions for its backhaul network, mesh technology’s capabilities can boost extending coverage of service areas easily and flexibly. For further cost reduction, a large-scale high-capacity mesh is desirable, for instance, Kyushu Universitys Mimo-Mesh Project, based in Fukuoka City, Fukuoka Prefecture, Japan, has developed and put into use new technology for building high capacity mesh infrastructure. A key component is called IPT, intermittent periodic transmit, a proprietary packet-forwarding scheme that is designed to reduce radio interference in the path of mesh networks. That network uses a wireless multi-hop relay of up to 11 access points while delivering high bandwidth to end users, actual throughput is double that of standard mesh network systems using conventional packet forwarding. Latency, as in all multi-hop relays, suffers, but not to the degree that it compromises voice over IP communications, many common wireless mesh network hotspot solutions are supported in open source router firmware including DD-WRT, OpenWRT and derivatives. Sputnik Agent, Hotspot System, Chillispot and the ad-supported AnchorFree are four examples that work even with lower end routers like the WRT54G. The IEEE802.21 standard specifies basic capabilities for such systems including 802. 11u unknown user authentication and 802. 11s ad hoc wireless mesh networking support
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Telecommunications network
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A telecommunications network is a collection of terminal nodes, links are connected so as to enable telecommunication between the terminals. The transmission links connect the nodes together, the nodes use circuit switching, message switching or packet switching to pass the signal through the correct links and nodes to reach the correct destination terminal. Each terminal in the network usually has an address so messages or connections can be routed to the correct recipients. The collection of addresses in the network is called the address space, for example, businesses need a greater telecommunications network if they plan to expand their company. With Internet, computer, and telephone networks, businesses can allocate their resources efficiently and these core types of networks will be discussed below, Computer network, a computer network consists of computers and devices connected to one another. Information can be transferred from one device to the next, for example, an office filled with computers can share files together on each separate device. Computer networks can range from a local area to a wide area network. The difference between the types of networks is the size and these types of computer networks work at certain speeds, also known as broadband. The Internet network connects computers worldwide, Internet network, access to the network allows users to use many resources. Over time the Internet network will replace books and this will enable users to discover information almost instantly and apply concepts to different situations. The Internet can be used for recreational, governmental, educational, businesses in particular use the Internet network for research or to service customers and clients. Telephone network, the network connects people to one another. This network can be used in a variety of ways, many businesses use the telephone network to route calls and/or service their customers. Some businesses use a network on a greater scale through a private branch exchange. It is a system where a specific business focuses on routing and servicing calls for another business, majority of the time, the telephone network is used around the world for recreational purposes. In general, every telecommunications network conceptually consists of three parts, or planes, The data plane carries the networks users traffic, the actual payload, the control plane carries control information. The management plane carries the operations and administration traffic required for network management, the management plane is sometimes considered a part of the control plane. The data network is used throughout the world to connect individuals
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General Services Administration
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The General Services Administration is an independent agency of the United States government, established in 1949 to help manage and support the basic functioning of federal agencies. GSA employs about 12,000 federal workers and has an operating budget of roughly $26.3 billion. GSA oversees $66 billion of procurement annually and it contributes to the management of about $500 billion in U. S. federal property, divided chiefly among 8,300 owned and leased buildings and a 210,000 vehicle motor pool. GSAs business lines include the Federal Acquisition Service, the Public Buildings Service, the GSA is member of the Procurement G6, an informal group leading the use of framework agreements and e-procurement instruments in public procurement. In 1947 President Harry Truman asked former President Herbert Hoover to lead what became known as the Hoover Commission to make recommendations to reorganize the operations of the federal government, one of the recommendations of the commission was the establishment of an Office of the General Services. This proposed office would combine the responsibilities of the following organizations, General Jess Larson, Administrator of the War Assets Administration, was named GSAs first Administrator. The first job awaiting Administrator Larson and the newly formed GSA was a renovation of the White House. The structure had fallen into such a state of disrepair by 1949 that one inspector of the time said the structure was standing “purely from habit. Everything, except the four walls without a roof, was stripped down. GSA completed the renovation in 1952, GSA headquarters, located at Eighteenth and F Streets, NW, was U. S. General Services Administration Building listed on the National Register of Historic Places in 1986 as Interior Department Offices, in 1960, GSA created the Federal Telecommunications System, a government-wide intercity telephone system. In 1970, the Nixon administration created the Consumer Product Information Coordinating Center, the Federal Buildings Fund was initiated in 1974, which allowed the GSA to issue rent bills to federal agencies. In 1972, the GSA established the Automated Data and Telecommunications Service, in 1973, the GSA created the Office of Federal Management Policy. GSA’s Office of Acquisition Policy centralized procurement policy in 1978, in 1984, GSA introduced the federal government to the use of charge cards, known as the GMA SmartPay system. The National Archives and Records Administration was spun off into an independent agency in 1985, the same year, the GSA began to provide governmentwide policy oversight and guidance for federal real property management as a result of an Executive Order signed by President Ronald Reagan. In 2003, the Federal Protective Service was moved to the Department of Homeland Security, in 2005, GSA reorganized to merge the Federal Supply Service and Federal Technology Service business lines into the Federal Acquisition Service. On April 3,2009, President Barack Obama nominated Martha N. Johnson to serve as the GSA Administrator, after a 9-month delay, the United States Senate confirmed her nomination on February 4,2010. In July 1991, GSA contractors began the excavation of what is now the Ted Weiss Federal Building in New York City, when initial excavation disturbed burials, destroying skeletons and artifacts, GSA sent archaeologists to excavate—but hid their findings from the public
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MIL-STD-188
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MIL-STD-188 is a series of U. S. military standards relating to telecommunications. S. Department of Defense looked to develop a series of standards that would alleviate the problem, … systems developed for use by U. S. forces are considered to be for joint use. The MIL-STD-188 standards were created to address telecommunication design parameters based on proven technologies, to ensure interoperability, DISA made these standards mandatory for use in all new DoD systems and equipment, or major upgrades. The mandatory use of standards will aid significantly in achieving standardization and result in improvements in availability, maintainability, reliability. This, in turn, will enhance lifecycle configuration management and logistic support with subsequent reductions in life cycle costs, in line with a decision by the Joint Chiefs of Staff, these standards are published in the MIL-STD-188 series of documents. The MIL-STD-188 series standards are encompassed by the DoD’s Joint Technical Architecture, for any DoD Agency to get a waiver to receive an item that deviates from the standards they also must apply to the JSC. Currently the DoD is placing its emphasis on the development of standards for tactical. Note, The following list of documents are those that are presently active, documents with three digit numbers followed by a letter of the alphabet indicate that they are revisions of an older version of that document. According to the DoD the MIL-STD-188-100 series contains technical standards and design objectives which are common to both the long haul and tactical communications systems, database with most MILSTD and DEFSTAN publications
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United States Department of Defense
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The Department is the largest employer in the world, with nearly 1.3 million active duty servicemen and women as of 2016. Adding to its employees are over 801,000 National Guardsmen and Reservists from the four services and it is headquartered at the Pentagon in Arlington, Virginia, just outside of Washington, D. C. The Department of Defense is headed by the Secretary of Defense, Military operations are managed by nine regional or functional Unified Combatant Commands. The Department of Defense also operates several joint services schools, including the National Defense University, the history of the defense of the United States started with the Continental Congress in 1775. The creation of the United States Army was enacted on 14 June 1775 and this coincides with the American holiday Flag Day. The Second Continental Congress would charter the United States Navy, on 13 October 1775, today, both the Navy and the Marine Corps are separate military services subordinate to the Department of the Navy. The Preamble of the United States Constitution gave the authority to federal government, to defend its citizens and this first Congress had a huge agenda, that of creating legislation to build a government for the ages. Legislation to create a military defense force stagnated, two separate times, President George Washington went to Congress to remind them of their duty to establish a military. In a special message to Congress on 19 December 1945, the President cited both wasteful military spending and inter-departmental conflicts, deliberations in Congress went on for months focusing heavily on the role of the military in society and the threat of granting too much military power to the executive. The act placed the National Military Establishment under the control of a single Secretary of Defense, the National Military Establishment formally began operations on 18 September, the day after the Senate confirmed James V. Forrestal as the first Secretary of Defense. The National Military Establishment was renamed the Department of Defense on 10 August 1949, under the Department of Defense Reorganization Act of 1958, channels of authority within the department were streamlined, while still maintaining the authority of the Military Departments. Also provided in this legislation was a centralized authority, the Advanced Research Projects Agency. The Act moved decision-making authority from the Military Departments to the Joint Chiefs of Staff and it also strengthened the command channel of the military over U. S. forces from the President to the Secretary of Defense. Written and promoted by the Eisenhower administration, it was signed into law 6 August 1958, because the Constitution vests all military authority in Congress and the President, the statutory authority of the Secretary of Defense is derived from their constitutional authorities. Department of Defense Directive 5100.01 describes the relationships within the Department. The latest version, signed by former Secretary of Defense Robert Gates in December 2010, is the first major re-write since 1987, the Office of the Secretary of Defense is the Secretary and Deputy Secretarys civilian staff. S. Government departments and agencies, foreign governments, and international organizations, OSD also performs oversight and management of the Defense Agencies and Department of Defense Field Activities. OSD also supervises the following Defense Agencies, Several defense agencies are members of the United States Intelligence Community and these are national-level intelligence services that operate under the jurisdiction of the Department of Defense but simultaneously fall under the authorities of the Director of National Intelligence
This article incorporates public domain material from the General Services Administration document "Federal Standard 1037C" (in support of MIL-STD-188).
This article incorporates public domain material from the United States Department of Defense document "Dictionary of Military and Associated Terms".