The public switched telephone network pstn the telephone is connected to the telephone switch with two copper wires, often called a local loop or a subscriber loop, or simply a loop. Gsm tutorial gsm is a globally accepted standard for digital cellular communications. Later, the operators were replaced by electromechanical automatic telephone exchanges but circuit switching was still used to establish analog phone calls on our pstn public switched telephone network which is also known as pots post office telephone service or plain old telephone system. Understanding the fundamentals of this technology and network architecture is the starting point for understanding everything else. A telephone is an instrument that resides on a telephone network. The voice digitization, compression or conversion back to analog data need the implementation. Many organizations are transitioning away from traditional voice services in favor of voice over ip. The public switched telephone network pstn is used for the landline telephone system. Finally, a connection is made and communication is.
Today the term plain old telephone service is used, after the services were removed from the control of national post offices. Databases hlr home location register vlr visitor location register eir equipment identity register network subsystem msc msc fixed partner networks iwf isdn pstn pspdn cspd n s s 7 eir hlr vlr isdn pstn. The interconnection to the public switched telephone network pstn. Voip delivers voice traffic over the internet rather than the legacy public switched telephone network, which offers organizations cost savings, more advanced features and other benefits. Gsm network areas the gsm network is made up of geographic areas.
Public switched telephone network pstn or integrated services digital network isdn. The information is carried by a signal, which is certain physical quantity that changes with time. A telephone call is established when the number is dialed. The public switched telephone network consists of the local and toll automatic exchanges, switching nodes, lines and channels of telephone network and subscriber telephone terminals. Cost savings from integration into the data network toll charges for interoffice voice communication can be avoided by routing voice. Ipsec, vpn, and firewall concepts computer science. The public switched telephone network pstn is the aggregate of the worlds circuitswitched telephone networks that are operated by national, regional, or local telephony operators, providing infrastructure and services for public telecommunication. Loops and trunks, co, telephone switches and circuitswitching.
Learn about uc and its many layers, including terminals, applications, codecs, gateways, realtime protocols, and network operations, so you can integrate uc and voip into your business network. A public switched telephone network is a combination of telephone networks used worldwide, including telephone lines, fiber optic cables, switching centers, cellular networks, satellites and cable systems. Evolution of pstn inception 1876 invention of the first telephone by sir alexander graham bell 28th january 1878 worlds first telephone exchange was established at newhaven in connecticut in the usa telephones were sold in pairs and the customers were supposed to lay out there own cables connectivity type point to point. Both of them refer to use the same ip network to send voice messages. Basic network design fundamental components of a wireless system there are five main components to a wireless network. Ppp pointtopoint protocol a protocol that tunnels multiple networklayer protocols. The public switched telephone network pstn, also known as plain old. Pstn public switched telephone network any of a variety of telephone networks and services in place worldwide. Public switched telephone network linkedin slideshare. The telephone network university of texas at dallas. A pstn lets users make landline telephone calls to one another. This is known as the public switched telephone network or pstn. It identifies functions to be performed by a signalingsystem network and a protocol to enable their performance.
But the main difference between voip and ip telephony is that voip is connecting old fashion analog phones to specific gateway device who are able to convert analog voice data into digital bits and send them across the internet bypassing the expensive pstn telephone networks. The communication between different users of wan is established using leased telephone lines. Signaling system 7 ss7 is an architecture for performing outofband signaling in support of the callestablishment, billing, routing, and informationexchange functions of the public switched telephone network pstn. The customers part today is largely just the telephone, some house wiring, and some connectors. When two telephones are connected, analog voice data is transmitted over the copper wires of the pstn. To connect one phone to another, the phone call is routed through numerous switches operating on a local, regional, national or international level. Another term commonly used for it is pots, which stands for plain old telephone system, a nongeek way of naming the landline phone system that is being rapidly replaced by newer digital and mobile providers. Pstn customers connect to the endoffice eo for telecommunications services. Sep 28, 2017 public switched telephone network ch10 applied sc, allied physical and chemical sc. A central office switch has connections to homes and offices end. Basics of pstn free download as powerpoint presentation.
Continue reading to learn more about the pstn basics and how the network functions. This was bad, because as a voice went farther down the line, and through more switches, the quality became worse and worse as noise crept in. But implementing voip is no small task and enterprises must be prepared to migrate. Even though a voip phone system uses voip and is connected to your lan, most systems can connect directly to the publicly switched telephone network pstn. In the pstn, the famous last mile is the final remaining piece of the telephone net work still using technology pioneered well over a hundred years ago. Pstn or public switched telephone network is simply or most commonly known as a telephone line. Some important concepts in telecommunications are as follows. An introduction to basic telephony concepts white paper 3 application system telephone network party a party b ss7 subnetwork telephone switch telephone switch talk paths ss7 signaling paths figure 1. To connect one phone to another, the phone call is routed through numerous switches operating on a local, regional, national or. Lesson 1 introduction to voip technology and a lan port.
Ppt pstn telephone network powerpoint presentation. Wide area network wan when network spans over a large distance or when the computers to be connected to each other are at widely separated locations a local area network cannot be used. Cellular networks khoury college of computer sciences. Ppt pstn telephone network powerpoint presentation free. Oct 11, 20 evolution of pstn inception 1876 invention of the first telephone by sir alexander graham bell 28th january 1878 worlds first telephone exchange was established at newhaven in connecticut in the usa telephones were sold in pairs and the customers were supposed to lay out there own cables connectivity type point to point. With the invention of voip, phone calls could be made over the same ip data networks that your computer and now smartphone and tablets leverages for web browsing, email, etc.
Isdn overview motivation and history a long time ago, the entire telephone network was analog. Until about the 1980s, traditional phone calls were made via the public switched telephone network pstn over copper wiring and switches. Isdn integrated services digital network combines voice connection and digital data services in a single physical medium the pstn isdn network is the largest telecom network worldwide, interconnecting about onesixth of the world population. This enables a user to plug into the fxs port an analog telephone, and then attach the ata to the network with an utp cable. A tandem switch switches traffic between central offices and forms the core of the network. End central office smallest, lowest, most common toll center primary center secondary center regional center largest, highest, least common. A connection between the caller and the phone be called is established when the last digit is dialed. Public switched telephone network ch10 applied sc, allied physical and chemical sc. Pstn public switched telephone network pspdn packet switched public data net. The course is completed with an overview of ss7, the control system for the telephone network in the us and canada. It is possible to use voicefrequency channels and digital channels of various transmission systems cable, microwave, satellite as channels of the telephone network. How voice signals are carried over the public switched telephone network. In this paper we will use network analysis to study the pstn.
As enterprises move on from legacy voice communications systems like the publicswitched telephone network pstn, session initiation protocol sip trunking has emerged as a popular method of facilitating voice communications over the internet. The public switched telephone network howstuffworks. Standardized digital techniques for switching and transmission t1 etc q 1980. A landline network where the telephones must be directly wired into a single telephone exchange. On completion of this course, you will be able to draw a model of the public switched telephone network, identify and explain its components and technologies including. But implementing voip is no small task and enterprises must be prepared to migrate their voice services with minimal disruption.
The public switched telephone network pstn is the aggregate of the worlds circuitswitched. Ppp pointtopoint protocol a protocol that tunnels multiple network layer protocols. Cost savings from integration into the data network. A wireless network where the telephones are mobile and can move around anywhere within the coverage area. Gsm is a circuitswitched network, which means that there are two different types of physical links to transport control information signaling and traf. The pstn topology and class level might be different in different countries but the original design was only for circuit switching. Lisa bock compares the traditional public switched telephone network pstn to voip, and discusses the framework and components necessary for voip to. Topic 1200 introduction to public switched telephone. The public switched telephone network pstn, also known as plain old telephone service pots, is the wired phone system over which landline telephone calls are made. Mobile phone to public switched telephone network pstn when a mobile subscriber makes a call to a pstn telephone subscriber, the following sequence of events takes place. The signal can be a voltage proportional to the amplitude of the voice. In this course, well understand the public switched telephone network pstn, and plain ordinary telephone service pots. Pstn ppt public switched telephone network voice over ip.
As shown in figure 3, these areas include cells, location areas las, mscvlr service areas, and public land mobile network plmn areas. Pstn is the short form of public switched telephone network. Pstn uses an old technology whereby circuitswitched copper phone lines are used to transmit. This network is called the public switched telephone network pstn. The eo processes the customer service request locally or passes it off to the appropriate end or tandem office. This way the analog telephones will be available for voip calls too. That telephone network can be on a pbx private branch exchange phone system, or it can be on the pstn publ. Pstn is a centuryold worldwide connected telephone network. Pstnisdn pstn public switched telephone network interconnect almost every telephone set. This a dedicated access circuit from the customer premise into the network. Network areas the cell is the area given radio coverage by one base transceiver station. The telephone is connected to public switched telecommunications network pstn for local, national, and international voice communications the same connections can carry data and image information television the connection to the pstn may be via local exchange carriers lec endusers, nodes, and connectivities. Private branch exchange or pstn public switched telephone network.
The voice data is then converted into electrical signals which are eventually routed in the switching centers. But fiberoptic and other highbandwidth cables havent changed the basic nature. Jan 18, 2020 the public switched telephone network pstn is used for the landline telephone system. Alongside with the basic telephone, faximile, email and data calls handling pstn should provide also the following services. Public switched telephone network is the legacy switching system for providing conventional telephone service. Gsm uses narrowband time division multiple access tdma for providing voice and text based services over mobile phone networks. The ds0 circuit is the basic granularity of circuit switching in a telephone exchange. Nov 25, 2018 pstn is a centuryold worldwide connected telephone network. This is the most commonly used method by all users that only have the need to use one line for one conversation at a time using only one phone number. Our analysis of the pstn is focused on wired copper and fiber networks. Pptp pointtopoint tunneling protocol a microsoft protocol for layer 2 that serves the same purpose as l2tp. Other than pstn basics it mentions difference between pstn,isdn and psdn is also provided.
Basic network design electronic frontier foundation. Wide area networkwan when network spans over a large distance or when the computers to be connected to each other are at widely separated locations a local area network cannot be used. End central office smallest, lowest, most common toll center primary center secondary center. The connection follows a route through the telephone network. The pstn consists of telephone lines, fiber optic cables, microwave transmission links, cellular networks, communications satellites. Pstn isdn pstn public switched telephone network interconnect almost every telephone set. The public switched telephone network many communication technologies are based on those used in the public switched telephone network pstn, so regardless of whether youre interested in voice, data or networking, it is important to have an understanding of the structure and operation of the telephone network. Public switched telephone networks mit opencourseware. The basic pstn network link, or pots line supports 64 kbps bandwidth. One of the primary challenges when transmitting analog signals is that all sorts of. Audience this tutorial has been designed for readers who want to understand the basics of gsm in very simple terms. The telephone lines are connected to local exchanges.
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