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Components of a Telecommunication System

In its most fundamental form, a telecommunication system includes a transmitter to take information and convert it to a signal, a transmission medium to carry the signal and a receiver to take the signal and convert it back into usable information. This applies to any communication system, whether it uses computers or not.

Most modern day telecommunications systems are best described in terms of a network. This includes the basic elements listed above but also the infrastructure and controls needed to support the system. There are six basic components to a telecommunications network.

Input and output devices, also referred to as ‘terminals’: These provide the starting and stopping points of all communication. A telephone is an example of a terminal. In computer networks, these devices are commonly referred to as ‘nodes’ and consist of computer and peripheral devices.
Telecommunication channels, which transmit and receive data: This includes various types of cables and wireless radio frequencies.
Telecommunication processors, which provide a number of control and support functions: For example, in many systems, data needs to be converted from analog to digital and back.
Control software, which is responsible for controlling the functionality and activities of the network.
Messages represent the actual data that is being transmitted: In the case of a telephone network, the messages would consist of audio as well as data.
Protocols specify how each type of telecommunication systems handle the messages: For example, GSM and 3G are protocols for mobile phone communications, and TCP/IP is a protocol for communications over the Internet.

While early telecommunication systems were built without computers, almost all systems we use today are computerized in some way.

Computer Network

A computer network is a system of computers and peripheral devices that are connected electronically. These connected computers can communicate with each other, which means that they can share information. Each computer has its own network address, so it can be uniquely identified among all the computers in a network. Computer networks are able to carry different types of data and support different applications.

Computers are connected using a number of different types of communication channels. These include both wired and wireless connections. Wired connections consist of an actual physical cable, such as copper wire or fiber optics. Wireless connections do not use a physical cable but transfer data using waves at a particular part of the electromagnetic spectrum.

Why do we need a computer network? Transferring files between individual computers can be accomplished using physical media, such as DVDs or external hard drives, but a computer network makes it possible to transfer data between computers without having to use physical media.

Some of the advantages of computer networks are:

File sharing
Internet connection sharing
Sharing of peripheral devices
Improved cost efficiency
Increased storage capacity

The network itself can also carry out tasks that are difficult for any single computer to do. These network services have become increasingly important as many different types of devices are connected to each other.

Different Types of Networks

There are a number of different ways to describe computer networks, including network size, transmission media, management method and network topology. Network size relates to the geographic area occupied by the computers and the network and the behavior of the computers when data is shared. For example, a local area network, or LAN, consists of a computer network at a single site, typically an individual building. A wide area network, or WAN, occupies a very large area, such as an entire country or the entire world. The Internet is the best-known example of a WAN.

The transmission media of a computer network describes the material substances that carry energy waves, which include the data being transferred. The two main categories are wired connections, which use physical cables, and wireless connections, which use electromagnetic waves and do not require a physical medium. The most commonly used wired connections use twisted-pair cables, coaxial cables and fiber optic cables. The most commonly used wireless connections use radio waves, microwaves and infrared waves.

Management methods for networks include peer-to-peer, mainframes and client/server. In a peer-to-peer, or P2P, network, the tasks are allocated among all the members of the network, and there is no real hierarchy. In a client/server network, a number of network clients or workstations request resources or services from the network. One or more network servers manage and provide these resources or services. In mainframe systems, a very powerful computer does all of the processing, and very basic terminals are used to access the mainframe system.

Computers in a network have to be connected to each other in some sort of system. The layout of the interconnections between the computers in a network is called network topology. There are a number of different topologies, including point-to-point, bus, star, ring, mesh, tree and hybrid. Each one has its own unique strengths and weaknesses.

Network Properties

A computer network can also be described in terms of its properties. These include bandwidth, cost and reliability. Bandwidth is the amount of data that can be transferred over a network per second. Bandwidth is also referred to as ‘data transfer rate’ or ‘capacity’ and is typically expressed in megabits per second (Mbit/s or Mbps) or gigabits per second (Gbit/s or Gbps). For example, the bandwidth of a typical wireless network using Wi-Fi is between 11 and 54 Mbit/s, while the bandwidth of a typical wired Ethernet connection is 1 Gbit/s or more.

Cost of a network can be broken down into the cost of installing the network hardware, such as cables and switches, and the cost of running and maintaining the system. Reliability refers to how often the network does not perform as expected. Just like a regular desktop computer, a computer server can crash and stop working. More reliable networks have back-up systems in place so that if one server were to fail, another one takes over.

Lesson Summary

A telecommunications system is a collection of nodes and links to enable telecommunication. Examples of telecommunications systems are the telephone network, computer networks and the Internet.

The six basic components of a telecommunication system are:

Input and output devices
Telecommunication channels
Telecommunication processors
Control software
Messages
Protocols

A computer network is a system of computers and peripheral devices that are connected electronically. Computer networks can be described in terms of their size, transmission media, management method and network topology. Important properties of computer networks are bandwidth, cost and reliability.