An access network is a type of telecommunications network which connects subscribers to their immediate service provider. It is contrasted with the core network; the access network may be further divided between feeder plant or distribution network, drop plant or edge network. An access network referred to as an outside plant, refers to the series of wires and equipment lying between a consumer/business telephone termination point and the local telephone exchange; the local exchange contains banks of automated switching equipment which direct a call or connection to the consumer. The access network is one of the oldest assets a telecoms operator would own. In 2007–2008 many telecommunication operators experienced increasing problems maintaining the quality of the records which describe the network. In 2006, according to an independent Yankee Group report, globally operators experience profit leakage in excess of $17 billion each year; the access network is perhaps the most valuable asset an operator owns, since this is what physically allows them to offer a service.
Access networks consist of pairs of copper wires, each traveling in a direct path between the exchange and the customer. In some instances, these wires may consist of aluminum, used in the 1960s and 1970s following a massive increase in the cost of copper; as it happened, the price increase was temporary, but the effects of this decision are still felt today as electromigration within the aluminum wires can cause an increase in on-state resistance. This resistance causes degradation which can lead to the complete failure of the wire to transport data. Access is essential to the future profitability of operators who are experiencing massive reductions in revenue from plain old telephone services, due in part to the opening of nationalized companies to competition, in part to increased use of mobile phones and voice over IP services. Operators offered additional services such as xDSL based IPTV to guarantee profit; the access network is again the main barrier to achieving these profits since operators worldwide have accurate records of only 40% to 60% of the network.
Without understanding or knowing the characteristics of these enormous copper spider webs, it is difficult, expensive to'provision' new customers and assure the data rates required to receive next generation services. Access networks around the world evolved to include more optical fiber technology. Optical fibre makes up the majority of core networks and will start to creep closer and closer to the customer, until a full transition is achieved, delivering value added services over fiber to the home; the process of communicating with a network begins with an access attempt, in which one or more users interact with a communications system to enable initiation of user information transfer. An access attempt. An access attempt ends either in successful access or in access failure - an unsuccessful access that results in termination of the attempt in any manner other than initiation of user information transfer between the intended source and destination within the specified maximum access time.
Access failure can be the result of access outage, user blocking, incorrect access, or access denial. Access denial can include: Access failure caused by the issuing of a system blocking signal by a communications system that does not have a camp-on busy signal feature. Access failure caused by exceeding the maximum access time and nominal system access time fraction during an access attempt. An access charge is a charge made by a local exchange carrier for use of its local exchange facilities for a purpose such as the origination or termination of network traffic, carried to or from a distant exchange by an interexchange carrier. Although some access charges are billed directly to interexchange carriers, a significant percentage of all access charges are paid by the local end users. GERAN UTRAN E-UTRAN CDMA2000 GSM UMTS 1xEVDO voLTE Wi-Fi in* WiMAX A passive optical distribution network uses single mode optical fibre in the outside plant, optical splitters and optical distribution frames, duplexed so that both upstream and downstream signals share the same fibre on separate wavelengths.
Faster PON standards support a higher split ratio of users per PON, but may use reach extenders/amplifiers where extra coverage is needed. Optical splitters creating a point to multipoint topology are the same technology regardless of the type of PON system, making any PON network upgradable by changing the optical network terminals and optical line terminal terminals at each end, with minimal change to the physical network. Access networks also must support point-to-point technologies such as Ethernet, which bypasses any outside plant splitter to achieve a dedicated link to the telephone exchange; some PON networks use a "home run" topology where roadside cabinets only contain patch panels so that all splitters are located centrally. While a 20% higher capital cost could be expected, home run networks may encourage a more competitive wholesale market since providers' equipment can achieve higher use. Internet access IP Connectivity Access Network Local loop Passive Optical Network "The Network Story".
British Telecom. 2005. Archived from the original on 5 May 2010. Interactive presentation introducing the technology and design of access networks
Telecommunication is the transmission of signs, messages, writings and sounds or information of any nature by wire, optical or other electromagnetic systems. Telecommunication occurs when the exchange of information between communication participants includes the use of technology, 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. Since the Latin term communicatio is considered the social process of information exchange, the term telecommunications is used in its plural form because it involves many different technologies. Early means of communicating over a distance included visual signals, such as beacons, smoke signals, semaphore telegraphs, signal flags, optical heliographs. Other examples of pre-modern long-distance communication included audio messages such as coded drumbeats, lung-blown horns, loud whistles. 20th- and 21st-century technologies for long-distance communication involve electrical and electromagnetic technologies, such as telegraph and teleprinter, radio, microwave transmission, fiber optics, communications satellites.
A revolution in wireless communication began in the first decade of the 20th century with the pioneering developments in radio communications by Guglielmo Marconi, who won the Nobel Prize in Physics in 1909, other notable pioneering inventors and developers in the field of electrical and electronic telecommunications. These included Charles Wheatstone and Samuel Morse, Alexander Graham Bell, Edwin Armstrong and Lee de Forest, as well as Vladimir K. Zworykin, John Logie Baird and Philo Farnsworth; the word telecommunication is a compound of the Greek prefix tele, meaning distant, far off, or afar, the Latin communicare, meaning to share. Its modern use is adapted from the French, because its written use was recorded in 1904 by the French engineer and novelist Édouard Estaunié. Communication was first used as an English word in the late 14th century, it comes from Old French comunicacion, from Latin communicationem, noun of action from past participle stem of communicare "to share, divide out.
Homing pigeons have been used throughout history by different cultures. Pigeon post had Persian roots, was used by the Romans to aid their military. Frontinus said; the Greeks 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 Sumatra, and in 1849, Paul Julius Reuter started a pigeon 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. In the Middle Ages, chains of beacons were used on hilltops as a means of relaying a signal. Beacon chains suffered the drawback that they could only pass a single bit of information, so the meaning of the message such as "the enemy has been sighted" had to be agreed upon in advance. One notable instance of their use was during the Spanish Armada, when a beacon chain relayed a signal from Plymouth to London. 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. On 25 July 1837 the first commercial electrical telegraph was demonstrated by English inventor Sir William Fothergill Cooke, English scientist Sir Charles Wheatstone. 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, his code was an important advance over Wheatstone's signaling method. The first transatlantic telegraph cable was completed on 27 July 1866, allowing transatlantic telecommunication for the first time; the conventional telephone was invented independently by Alexander Bell and Elisha Gray in 1876. Antonio Meucci invented the first device that allowed the electrical transmission of voice over a line in 1849.
However Meucci's device was of little practical value because it relied upon the electrophonic effect and thus required users to place the receiver in their mouth to "hear" what was being said. The first commercial telephone services were set-up in 1878 and 1879 on both sides of the Atlantic in the cities of New Haven and London. Starting in 1894, Italian inventor Guglielmo Marconi began developing a wireless communication using the newly discovered phenomenon of radio waves, showing by 1901 that they could be transmitted across the Atlantic Ocean; this was the start of wireless telegraphy by radio. Voice and music had little early success. World War I accelerated the development of radio for military communications. After the war, commercial radio AM broadcasting began in the 1920s and became an important mass medium for entertainment and news. World War II again accelerated development of radio for the wartime purposes of aircraft and land communication, radio navigation and radar. Development of stereo FM broadcasting of radio
A voicemail system is a computer-based system that allows users and subscribers to exchange personal voice messages. The term is used more broadly to denote any system of conveying a stored telecommunications voice messages, including using an answering machine. Most cell phone services offer voice-mail as a basic feature; the term Voicemail was coined by Televoice International for their introduction of the first US-wide Voicemail service in 1980. Although VMI trademarked the term, it became a generic term used for referring to all automated voice services employing a telephone. Voicemail popularity continues today with Internet telephone services such as Skype, Google Voice and ATT that integrate voice and text services for tablets and smartphones Voicemail systems were developed in the late 1970s by Voice Message Exchange, they became popular in the early 1980s. In September 2012 a report from USA Today and Vonage claimed; the report said that the number of voicemail messages declined 8 percent compared to 2011.
Voicemail systems are designed to convey a caller's recorded audio message to a recipient. To do so they contain a user interface to select and manage messages. Most systems use phone networks, either cellular- or landline-based, as the conduit for all of these functions; some systems may use multiple telecommunications methods, permitting recipients and callers to retrieve or leave messages through multiple methods such as PCs, PDA, Cellphones or Smartphones. Simple voicemail systems function as a remote answering machine using touch-tones as the user interface. More complicated systems may use other input devices such as a computer interface. Simpler voice-mail systems may play the audio message through the phone, while more advanced systems may have alternative delivery methods, including email or text message delivery, message transfer and forwarding options, multiple mailboxes. All modern voicemail systems use digital storage and are stored on computer data storage. Notification methods vary based on the voice-mail system.
Simple systems may not provide active notification at all, instead requiring the recipient to check with the system, while others may provide an indication that messages are waiting. More advanced systems may be integrated with a company’s PABX, with a call center ACD for automatic call distribution. Interactive Voice Response systems may use digital information stored in a corporate data base to select pre-recorded words and phrases stored in a voice-mail vocabulary to form sentences that are delivered to the caller; the conventional solution to efficient handling of telephone communication in businesses was the "message center." A message center or "message desk" was a centralized, manual answering service inside a company staffed by a few operators who answered all incoming phone calls. Extensions that were busy or rang "no answer" would forward to the message center using a device called a "call director"; the call director had a button for each extension in the company which would flash when that person's extension forwarded to the message center.
A little label next to the button told the operator the person being called. While it was an improvement over basic multi-line systems, the message center had many disadvantages. Many calls would come in at peak periods, such as lunch time, operators were busy; this left message attendants with little time to take each message accurately. They were not familiar with employees' names and "buzzwords" and how to spell or pronounce them. Messages were scribbled on pink slips and distributed by the internal mail system and messages arrived at people's desks after lengthy delays, contained little content other than the caller's name and number, were inaccurate, with misspelled names and wrong phone numbers. Tape-based telephone answering machines had come into the residential telephone market, but they weren't used much in the corporate environment due to physical limitations of the technology. One answering machine was needed for each telephone. Further, the manufacturers of PBXs used proprietary digital phone sets in order to increase the functionality and value of the PBX.
These phone sets were, by design, incompatible with answering machines. In the 1970s and early 1980s, the cost of long distance calling decreased and more business communications were conducted by telephone; as corporations grew and labor rates increased, the ratio of secretaries to employees decreased. With more communication by phone, multiple time zones, fewer secretaries, real-time phone communications were hampered by callers being unable to reach people; some early studies showed that only 1 in 4 phone calls resulted in a completed call and ha
A telephone call is a connection over a telephone network between the called party and the calling party. The first telephone call was made on March 1876 by Alexander Graham Bell. Bell demonstrated his ability to "talk with electricity" by transmitting a call to his assistant, Thomas Watson; the first words transmitted were "Mr Watson, come here. I want to see you."This event has been called Bell's "greatest success", as it demonstrated the first successful use of the telephone. Although it was his greatest success, he refused to have one in his own home because it was something he invented by mistake and saw it as a distraction from his main studies. A telephone call may carry ordinary voice transmission using a telephone, data transmission when the calling party and called party are using modems, or facsimile transmission when they are using fax machines; the call may use mobile phone, satellite phone or any combination thereof. When a telephone call has more than one called party it is referred to as a conference call.
When two or more users of the network are sharing the same physical line, it is called a party line or Rural phone line. If the caller's wireline phone is connected directly to the calling party, when the caller takes their telephone off-hook, the calling party's phone will ring; this is called a hot ringdown. Otherwise, the calling party is given a tone to indicate they should begin dialing the desired number. In some cases, if the calling party cannot dial calls directly, they will be connected to an operator who places the call for them. Calls may be placed through a public network provided by a commercial telephone company or a private network called a PBX. In most cases a private network is connected to the public network in order to allow PBX users to dial the outside world. Incoming calls to a private network arrive at the PBX in two ways: either directly to a users phone using a DDI number or indirectly via a receptionist who will answer the call first and manually put the caller through to the desired user on the PBX.
Most telephone calls through the PSTN are set up using ISUP signalling messages or one of its variants between telephone exchanges to establish the end to end connection. Calls through PBX networks are set up using DPNSS or variants; some types of calls are not charged, such as local calls dialed directly by a telephone subscriber in Canada, the United States, Hong Kong, United Kingdom, Ireland or New Zealand. In most other areas, all telephone calls are charged a fee for the connection. Fees depend on the provider of the service, the type of service being used and the distance between the calling and the called parties. In most circumstances, the calling party pays this fee. However, in some circumstances such as a reverse charge or collect call, the called party pays the cost of the call. In some circumstances, the caller pays a flat rate charge for the telephone connection and does not pay any additional charge for all calls made. Telecommunication liberalization has been established in several countries to allows customers to keep their local phone provider and use an alternate provider for a certain call in order to save money.
A typical phone call using a traditional phone is placed by picking the phone handset up off the base and holding the handset so that the hearing end is next to the user's ear and the speaking end is within range of the mouth. The caller rotary dials or presses buttons for the phone number needed to complete the call, the call is routed to the phone which has that number; the second phone makes a ringing noise to alert its owner, while the user of the first phone hears a ringing noise in its earpiece. If the second phone is picked up the operators of the two units are able to talk to one another through them. If the phone is not picked up, the operator of the first phone continues to hear a ringing noise until they hang up their own phone. One of the main struggles for Alexander Graham Bell and his team was to prove to non-English speakers that this new phenomenon "worked in their language." It was a concept, hard for people to understand at first. In addition to the traditional method of placing a telephone call, new technologies allow different methods for initiating a telephone call, such as voice dialing.
Voice over IP technology allows calls to be made through a PC. Other services, such as toll-free dial-around enable callers to initiate a telephone call through a third party without exchanging phone numbers. No phone calls could be made without first talking to the Switchboard operator. Using 21st century mobile phones does not require the use of an operator to complete a phone call; the use of headsets is becoming more common for receiving a call. Headsets can either be wireless. A special number can be dialed for operator assistance, which may be different for local vs. long-distance or international calls. Preceding and after a traditional telephone call is placed, certain tones signify the progress and status of the telephone call: a dial tone signifying that the system is ready to accept a telephone number and connect the call either: a ringing tone signifying that the called party has yet to answer the telephone a busy signal signifying that the called party's telephone is being used in a telephone call to another person a fast busy signal (also called reorder tone or overflow bu
Telephony is the field of technology involving the development and deployment of telecommunication services for the purpose of electronic transmission of voice, fax, or data, between distant parties. The history of telephony is intimately linked to the development of the telephone. Telephony is referred to as the construction or operation of telephones and telephonic systems and as a system of telecommunications in which telephonic equipment is employed in the transmission of speech or other sound between points, with or without the use of wires; the term is used to refer to computer hardware and computer network systems, that perform functions traditionally performed by telephone equipment. In this context the technology is referred to as Internet telephony, or voice over Internet Protocol; the first telephones were connected directly in pairs. Each user had a separate telephone wired to the locations he or she might wish to reach; this became inconvenient and unmanageable when people wanted to communicate with more than a few people.
The inventions of the telephone exchange provided the solution for establishing telephone connections with any other telephone in service in the local area. Each telephone was connected to the exchange via the local loop. Nearby exchanges in other service areas were connected with trunk lines and long distance service could be established by relaying the calls through multiple exchanges. Switchboards were manually operated by an attendant referred to as the "switchboard operator"; when a customer cranked a handle on the telephone, it turned on an indicator on the board in front of the operator, who would plug the operator headset into that jack and offer service. The caller had to ask for the called party by name by number, the operator connected one end of a circuit into the called party jack to alert them. If the called station answered, the operator disconnected their headset and completed the station-to-station circuit. Trunk calls were made with the assistance of other operators at other exchangers in the network.
In modern times, most telephones are plugged into telephone jacks. The jacks are connected by inside wiring to a drop wire. Cables bring a large number of drop wires from all over a district access network to one wire center or telephone exchange; when a telephone user wants to make a telephone call, equipment at the exchange examines the dialed telephone number and connects that telephone line to another in the same wire center, or to a trunk to a distant exchange. Most of the exchanges in the world are interconnected through a system of larger switching systems, forming the public switched telephone network. After the middle of the 20th century and data became important secondary users of the network created to carry voices, late in the century, parts of the network were upgraded with ISDN and DSL to improve handling of such traffic. Today, telephony uses digital technology in the provisioning of telephone systems. Telephone calls can be provided digitally, but may be restricted to cases in which the last mile is digital, or where the conversion between digital and analog signals takes place inside the telephone.
This advancement has reduced costs in communication, improved the quality of voice services. The first implementation of this, ISDN, permitted all data transport from end-to-end speedily over telephone lines; this service was made much less important due to the ability to provide digital services based on the IP protocol. Since the advent of personal computer technology in the 1980s, computer telephony integration has progressively provided more sophisticated telephony services and controlled by the computer, such as making and receiving voice and data calls with telephone directory services and caller identification; the integration of telephony software and computer systems is a major development in the evolution of office automation. The term is used in describing the computerized services of call centers, such as those that direct your phone call to the right department at a business you're calling. It's sometimes used for the ability to use your personal computer to initiate and manage phone calls.
CTI is not a new concept and has been used in the past in large telephone networks, but only dedicated call centers could justify the costs of the required equipment installation. Primary telephone service providers are offering information services such as automatic number identification, a telephone service architecture that separates CTI services from call switching and will make it easier to add new services. Dialed Number Identification Service on a scale is wide enough for its implementation to bring real value to business or residential telephone usage. A new generation of applications is being developed as a result of standardization and availability of low cost computer telephony links. Starting with the introduction of the transistor, invented in 1947 by Bell Laboratories, to amplification and switching circuits in the 1950s, through development of computer-based electronic switching systems, the public switched telephone network has evolved towards automation and digitization of signaling and audio transmissions.
Digital telephony is the use of digital electronics in the operation and provisioning of telephony systems and services. Since the 1960s a digital core network has replaced the traditional analog transmission and signaling systems, much of the access network has been digitized. Digital