Concept of Communication System- Bikram Adhikari

 The  term  communication  refers  to  the  sending,  receiving  and  processing  of  information  by  electronic media. It started with wire telegraphy in the eighteen forties (1840s), developing with telephony  some  decades  later  and  radio  at  the  beginning  of  this  century.  Radio  communicationwas made possible by the invention of the triode tube (one kind of vacuum tube). It was greatly stimulated by the work done during World War II. Consequently, it became even more widely used and refined through the invention and use of the transistor, integrated circuits, and other semiconductor   devices.   More   recently,   the   use   of   satellites   and   fiber   optics   has   made   communications  even  more  widespread,  with  an  increasing  emphasis  on  computer  and  other  data communications.

A modern  communication  system  is  first  concerned  with the processing and storing of information before its   transmission.   The   forms   of   communicationinclude      radio      telephony      and      telegraphy,      broadcasting,       point-to-point,       and       mobile       communications,  computer  communications,  and  radio aids to navigation.  

When   the   computer   was   first   introduced   in   scientific  work  and  business  –  a  medium-sized  company  or  university  might  have  one  or  few  computers, while large institutions had at most a few dozens.  

The  merging  of  computers  and  communications  has  had  a  profound  influence  on  the  way  the  computer   system   is   organized.   The   old   model   of   a   single   computer   serving   all   of   the   organization’s  computational  needs  has  been  replaced  by  one  in  which  a  large  number  of  separate but interconnected computers do the job. This system is called- “Computer Network.”

A computernetwork  is  defined  as  two  or  more  computing  devices  linked  together  to  communicate,  sharing  information  (files  and  software  programs)  and  other  hardware  resources  (printers,  hard  disks,  plotters).  The  concept  of  connected  computers  sharing  resources  is  called  networking.  Most  networks  are  constructed  around  a  cable  connection  that  links  the  computers.  This  connection  permits the computers to share (talk and listen) through a wire. More recently, several wireless solutions have become available: Infrared ports, Bluetooth, radio links, Wi-Fi, satellite and other protocols allow a variety of new devices to link with PCs. 

Advantages of using Computer Network

Some of the advantages of using computer network are:  

1.      Resource      sharing:

Sharing a resource is an important area in which a network exceeds the stand-alone computer. Most institutions cannot afford enough laser printers, fax machines, MODEMs,   scanners,   and   CD-ROM   players   for   each   computer.   However,   if   these   peripherals are added to a network, they can be shared by all users in a node (computers are in a network is known as a node.) 

2.     Centralized  control  and  management:  

The  networks  provide  centralized  control  and  management.  The  entire  computers  in  the  network  are  normally  connected  to  a  server,  which  defines  the  policy  and  security  measures  for  the  resources  used  by  the  network  members. 

3.      Speedy  and  cost-effective  communication:

Since  the  entire  computer  is  connected,  the  message can send from one computer to another within few seconds. 

4. Backup and recovery: 

Data are securely handled by the server and provide the mechanism for the backup in other devices with the use of the network. Similarly, the network is also used  to  recover  data  and  system  in  case  of  system  crash  using  backup  or  through  the  server. 

5.     Flexible     access:     

The  network  allows  people  to  easily  access  their  files  from  any  computer  throughout the network.  

6.     Workgroup     computing:     

Workgroup software (such as Microsoft Office) allows many users to  work  on  a  document  or  project  concurrently.  For  example,  experts  located  at  various  schools within a county could simultaneously contribute their ideas about new curriculum standards to the same document.

Disadvantages of using Computer Network

Some of the disadvantages of using computer network are:  

1.     Expensive:  

For  connecting  computers,  some  extra  devices  and  resources  like  NIC,  Hub,  cables are required, which increases the cost of operation. 

2.     Security     problem:  

Data  are  shared  in  a  public  medium  so  extra  precaution  is  needed  for  secure  transmission  and  storage.  In  addition,  due  to  the  connected  computers,  there  is  an  increase  in  computer  crimes  like  sending  viruses,  software  piracy,  hacking,  plagiarism,  pornography, spoofing. 

3.  Needs  special  technical  knowledge:  

Skilled  manpower  is  required  to  establish,  maintain  and operate a networking system. 

4. Network  Failure:  

Failure  of  the  network  may  hamper  the  day-to-day  operation  of  the  organization. For example, network failure in a bank may affect the transaction.


The network itself is difficult to establish, manage and operate

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