2. TELECOMMUNICATIONS AND NETWORKS
- If the sender and receiver of a message or information are not in the immediate vicinity of each other, for example in a
room, but exchange them over a more or less large distance, this is referred to as telecommunications.
- The term telecommunications is composed of the Greek word "tele" (far) and the Latin word "communicare" (to
communicate, to make common).
- When we speak of telecommunications today, we usually mean the transmission of information via cable or radio
technology, i.e., electronically. Letter post, telegraphy and fax have largely been replaced by e-mails, text messages,
mobile telephony and similar methods.
- The speed with which modern telecommunications operates or can operate is an essential prerequisite for our
economic system or for technical achievements such as space travel. Worldwide trade and globalization would not be
possible within the existing framework without telecommunications by cable or satellite. The same applies to future
trends such as autonomous driving, Industry 4.0 or the Internet of Things.
3. ANALOG AND DIGITAL SIGNAL (FUNCTIONSAND
COMPONENTS TELECOMMUNICATIONS)
- An analog signal is a physical quantity that can assume continuous values in the course of magnitude (amplitude) as
well as in the course of time.
- A digital signal is a physical quantity that can only assume certain discrete values.
- The values correspond to the number of agreed states. If two states are agreed, then these are digital signals.
- Analog signals consist of a continuous signal or data stream. This is not the case with digital signals. When digital
data is generated, it usually occurs explosively. The volume of data then often exceeds a level that can no longer be
processed. The data must then be stored temporarily so that it is not lost.
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4. COMMUNICATION CHANNELS (MEDIAAND DEVICES)
The transmission medium is an important component in communication technology. The transmission medium
is the path along which the signals and messages to be transmitted are transferred from the sender to the
receiver.
In communications technology, the entire transmission path usually consists of several successive
transmission sections. These sections can be composed of different transmission media.
In wire paths, the information signal is transmitted as a low-frequency or high-frequency electrical alternating
current. The transmission medium wire is a cable or a line whose basic material is metal. The metal is usually
insulated by a plastic, sometimes even additionally shielded.
Wires and cables are considered to be the simplest connection between twocommunication
participants. Wires and cables; Copper cable / telephone cable; Twistedpair cable; Coaxial cable
In radio paths, the information signal is transmitted as a high-frequency electromagnetic wave.The radio path
is free space, which is also referred to as the air interface. The signals are transmitted over freespace via
antennas at the transmitting and receiving stations. Obstacles, especially metallic objects, attenuate and
deflect the radio signals. This reduces the range of the radio signals.
Radio paths are usually slower and more unstable than wire paths. Radio technology; Radio technology - basic
terms; Antennas (radio technology)
In optical paths, the information signal is transmitted as an electromagnetic wavein the frequency range of
visible light within a light-conducting material. For example, made of glass, quartz or plastic fibers known as
fiber optic cables (FOC).
Fiber optic cables allow optical signals to bridge long distances without the need for amplifiers. Despite long
distances, a high bandwidth is possible. This makes fiber optics the transmission medium of the present and
future.
It is also conceivable to use free space and visible light for data transmission. Fiber optic cable (FOC) / fiber
optic cable; Fiber optic cable; Fiber optic components; VLC - Visible Light Communication
5. COMMUNICATIONS NETWORKS (NETWORK TOPOLOGIES)
A network topology is the typical arrangement and physical connection of devices in a network. Devices
are hosts, such as clients and servers, that actively use the network. This also includes network
components, such as switches and routers, which have a distribution function and ensure that all
network subscribers can establish a logical connection with each other. The network topology
determines the components to be used, as well as the access methods to the transmission medium.
Different Network Topologies:
Point-to-Point (PtP) / Point-to-Point (In a point-to-point topology, a simple and direct physical connection
exists only between two hosts or devices. The two devices can use these connections for mutual
communication.)
Point-to-Multipoint (PtMP) / point-to-multipoint (In a point-to-multipoint topology, several hosts are fed
by a central system. All hosts within the topology must share a line to the central system.)
Line / Chain / Line (In line topology, several hosts are connected to each other. A line is laid from host
to host. The two ends of the line are each terminated with a host.)
Bus (In the bus topology, all hosts are connected to each other via a common line. All hosts have
access to the transmission medium and the signals that are transmitted over it.)
Ring (The ring topology is a closed cable route in which the network nodes are connected with a
continuous cable ring. This means that one cable arrives at each host and one cable leaves.)
Star (In the star topology, there is one network component that maintains a physical connection to all
hosts. Each host is connected to the central network component via its own line.)
Tree (The tree topology is an extended star topology. Larger local networks have this structure)
Mesh Topology (The mesh topology or meshed topology is a decentralized network that does not have
to be subject to any binding structures and in which all network nodes are connected to each other in
some way.)
Fully Connected Topology (Fully Connected refers to a topology in which all hosts are connected to each
other. What is meant by this is that every host has its own physical connection to every host)
Fabric (A fabric has a star structure, but it does not have a central node; instead, it redundantly
connects the distributing components to form a structured meshed topology)
6. ELECTRONIC COMMERCE AND ELECTRONIC BUSINESS
TECHNOLOGIES
Electronic Data Interchange (EDI) - Refers to the electronic exchange of
structured data in accordance with defined standards between
business partners and enables data processing without manual entry.
Common EDI standards include EDIFACT, Odette, VDA, ANSI X.12 and
various XML formats.
The electronic data exchange works as follows: The document, e.g,
invoice (INVOIC) is generated with all necessary information from the
issuer's ERP/merchandise management program. The EDI converter
converts the data into the recipient's agreed format and transmits it. As
soon as the EDI message arrives at the recipient, the data is adapted to
the recipient's ERP data structure and processed there.
7. ENTERPRISE
NETWORK AND
INTERNET
WORKING
Enterprise networkingtraditionally focuses onLAN standards with hardware
switches, routerdevices, Ethernet cabling, WLAN connections and integrated
firewall software. These components are oftenused to build a local area network.
Enterprise networkingis the central aspect of all modern IT departments worldwide
and has always servedas a classic career path for millions of people. Every single
company has to developits individual networkingsolution depending on workflows,
production processes, customerrequirements, logistics, etc.
Internetworkingrefers to the connectionof two or more computer networks. Inthis
context, the term network refers to locally restrictednetworks (LAN). Routers enable
or regulate the flow of data betweenthe networks. Among other things, they are
responsible for selecting the path of the data through the various networks
(routing). The use of multiple routers oftenmeans that severalnetworks are
combined to form a large-scale network (WAN).
Internetworkingallows networks of different networkingtechnologies to be
connected, e.g. Ethernet with TokenRing. For this purpose, internetworkinguses a
common network protocolthat can be used on all supportednetworking
technologies
8. STANDARDS AND CONNECTIVITY FOR DIGITAL INTEGRATION
Digital integration is the idea that data or information on a
particular electronic device can be read or edited by another device
using a standard format.
Open Systems Interconnect (OSI) - To ensure flawless
communication between devices from different manufacturers and
to standardize them, a reference model has become established in
IT: the ISO/OSI layer model. It divides the Internet into seven
different, finely structured layers, all of which cooperate with and
among each other and each of which performs specific tasks.
Targeted data transmission is thus guarantee
TCP/IP - is a group of protocols that form the basis for the Internet
and other networks.
ISP - Internet Service Provider (ISP) is a very general term that
describes any service provider that offers services related to the
Internet.
9. INTERNET TECHNOLOGY AND SERVICES (TOOLS FOR
COMMUNICATION)
DNS - The Domain Name Systemmaps the name that users use to find a website to the
IP address that a computeruses to access a website.
LISTSERV - Listserv is an application program for mailing list management
Chatting – live conversations withotherpeople by using the internet
Instant Messaging - private channels communication
Internet Telephony (VolP) - Internet telephony, IP telephony or VoIP, refers to the
transmission of telephone calls and data via the Internet Protocol(IP) insteadof via the
traditional landline (PSTN), as with traditional analog telephony or ISDN
Telnet - Telnet is the name of a network protocolthat is less common on the Internet
today. This old and well-knownclient/serverprotocolis based on a character-oriented
data exchange overa TCP connection
File Transfer Protocol - It is therefore a so-calledprotocol, or more precisely, a
communication protocol. FTP is used to regulate the exchange of data betweenseveral
computers in a network.
Internet 2.0 - The term Web2.0 is not understood to mean a fundamentally new type of
technology or application, but rather the term describes a use of the Internet that has
changed in socio-technicalterms, in which its possibilities are consistently used and
further developed.
10. SEARCHING FOR INFORMATION ON THE WEB
SearchEngine - A searchengine is software forsearchingthe World Wide Webbased on
a mathematical algorithm for evaluating the relevance of web pages or content.
Shopping Bot - virtual agent that, like a search engine, searches online stores on the
World Wide Webfor specific products and low-price offers. Shopping bots lead to
improvedprice transparency and thus to greater price pressure.
Push Technology - The push model is a design patternfor data transmission in which the
data providermonitors the data. If this detects changes, it sends the changed values to
the data receiver. The receiverbehaves passively and waits for new values afterit has
registered according to the observerpattern. The opposite is the pull model.
Multicast - Multicast refers to a message transmission from one point to a group and is
therefore a form of multipoint connection. The technique is used in the network layer
according to the OSI model.
Firewall - A firewall is a security systemthat protects a computernetwork or a single
computerfrom unwantednetwork accesses
Extranet - The extranet is an extensionof the intranet by a component that can only be
used by a defined group of external users
Content Management System - A CMS is a computersoftware orapplication that uses a
database to manage content. It can be used in the development of a website. A CMS can
therefore be used to update content and/or the structure of a website.