What is Telecommunication Link?
A telecommunication link refers to a link or connection established between two or more places by means of a telecommunication system such as Voice calls, video calls, data or other information is transmitted through it. This type of link can be established by various means, such as cables (fiber optic or coaxial), wireless (radio waves, microwaves, satellites etc) or other communication mediums. Telecommunication links are used in everyday life in the form of Internet connections, telephone calls, TV broadcasts, etc.
Telecommunication Link Basics
The simplest form of a telecommunication link consist of two terminals and transmission media. Public telecommunication systems cater for a large number of customers, comprising a network. A network is a means of connecting users.
A call is originated at a traffic source and received at a traffic sink. Traffic is a term that quantified usage. Networks are configured to facilitate connections on an economical basis. There are two basic configuration, the mesh and star connection as given in the figure.
The use of centralized switching equipment. Single center, which reduces average length of transmission link as compared to figure.
Difference between Mash and Star Connection in Telecommunications Network System.
Mash Connection Connectivity.
Better connectivity
Each node is directly connected to another node. This leads to multiple paths between each node.
Redundancy
If one link goes down, data can go through other paths.
Performance High Reliability
Since each node is connected by multiple paths, the probability of failure of the entire network is reduced.
Less data traffic
Each node has a direct connection, so the data does not need multiple hops.
Complexity and cost
It is difficult to connect each node to all other nodes. High cost: Cost is high due to separate wiring and maintenance of each connection.
Star Connection Connectivity
Centralized Hub.
Each node is connected to a central hub or switch
Error
If the central hub goes down, the entire network is affected.
Performance Limited Redundancy
As each node depends on the central hub, redundancy is reduced.
Data Traffic
Data has to go through a central hub, which can increase the load on the hub.
Simplicity and cost
It is easy to design and install.
Low cost
Maintenance and wiring costs are reduced as only one cable runs from each node to the central hub.
Application of Mesh Connection
Mostly used in large and critical networks where reliability and redundancy are essential, eg: military networks, critical enterprise networks.
Application of Star Connection
Links and Nodes Comparison
The network compares links and nodes. The nodes are the switching points. The figure (A) depicts a distributed switching system. In the mesh agreements, (fig. A), the terminals and nodes are co-located and more number of links are required as compared to star configuration (fig.B). With one node, which is an example of centralized switching. It may be noted that all terminals most of the times are not originating traffic simultaneously. The mesh arrangements may be used where all the terminals are located in the same premises whereby the cost of line links is small or the links compare a radio channel. The possible arrangements for the two applications are given below.
Use of one channel per terminal. Each terminal is permanently connected to one channel, and all other terminals may across a particular terminal by operating a switch which connects it to the appropriate channel.
As above, but with less than N channels. (Mobile 📱 radio case)
Switching Center
For large networks, the area served may have a traffic pattern on a geographical Basics in addition to time diversity of usage. The division of the area into sectors served by local switching centers reduces the transmission network costs. The local switching centers are interconnected with trunk links, the number of which is determined by anticipated traffic (based on factors of interest) between the users in the two switching sectors.
Use of additional switching machine to reduce transmission cost further (if the terminals have a low utilization).
Variation of network cost with number of exchanges.
There is an optimum number of local switching centers for minimum total cost of transmission and switching. This depends upon the relative cost of switching and transmission equipment and the geographical distribution of terminal.
Hierarchical Network
On country-wide basis, several of such nodes may be required for inter-city and international traffic. The system is called Hierarchical Network of switching centers.
Gateway Exchange
The switching center which provide inter-city connection is called Tall Exchange and the international switching center is called Gateway Exchange.
Transmission Basics
Telecommunication signals are transmitted by line or wireless systems. The line transmission system comprises electrical, conducting, medium, or optical fiber and electronic devices for transforming electrical signals into light waves.
Wireless or Radio Systems
In wireless or radio systems, the signals are carried by the electromagnetic waves in the space between the transmitter and receiver. The distance between the transmitting and the receiving location causes spreading resulting in the diminishing of the transmitted power. For satisfactory detection at the receiving end, a certain level of signal power is necessary and depending upon this and the laws of the intervening medium, the power of the transmitter is determined.
On long routes, pre-created repeaters are necessary which regenerate or amplify the signal to the desired level. The transmitter with the required output power is used as the exclusive power may cause interference with other similar link in the vicinity due to electromagnetic induction. The interference level depends on the physical separation between the distributing and the distributed circuit in case of line communication and the frequency of operating is the dominant factor in radio communication.
What is means by transmission in telecommunication network system?
Data exchange
Transmission modes
Information is transmitted through analog signals, such as telephone calls.
Digital transmission
Information is transmitted through digital signals, such as Internet data.
Wired Transmission
Through wires, such as copper cables, fiber optic cables.
Wireless transmission
Wireless, such as radio waves, microwaves, satellite links.
Medium
Simplex Data is transmitted in one direction, like a TV broadcast.
Half Duplex
Data can be transmitted in both directions but not simultaneously, such as a walkie-talkie.
Full Duplex
Data can be transmitted in both directions simultaneously, such as a telephone.
Transmission Techniques
Packet Switching
Data is sent divided into small packets, each packet can take its own path, like Internet traffic.
Circuit switching
A circuit is established that is maintained throughout a complete data transmission, such as a traditional telephone call.
Challenges of transmission
Attenuation
A decrease in signal intensity.
Interference
Data corruption due to other signals or noise.
Bit Error Rate Proportion of errors in data.
Transmission is a fundamental part of a telecommunication network that ensures accurate and efficient transfer of information. Different transmission mediums and techniques are used under different conditions and requirements.
