Components of a Data Comm. Systems

Components of a Data Com Systems
Components of a Data Com Systems
Any system is made up of more than one component. Similarly, a data communication
system is made up of 5 components as shown in the fig:

• Message
• Sender
• Receiver
• Medium
• Protocol

MESSAGE

• Information or Data to be communicated
• Can be text, numbers, video or any combination of these
• In short anything that can be represented using binary bits

Data Communication Messages
Files (meaningful collections of records)
Data/information requests (database queries, Web page requests,
etc.)
Responses to requests and commands or error messages
Status messages (about the network’s functional status)
Control messages transmitted between network devices to control
network traffic
Correspondence among network users

MESSAGE TYPES

SENDER

• Device that sends the data message
• Can be a Computer , Workstation, Video camera etc
• As already discussed, the data from the sender might not be in the appropriate format for the transmission medium and will need to be processed

RECEIVER

• Device that receives the message
• Can be a computer, workstation, Television etc
• At times, the data received from the transmission medium may not be in a proper form to be supplied to the receiver and it must be processed

MEDIUM

• Physical path that a message uses to travel from the Sender to the Receiver
• Can be a Copper Cable (Telephone), Coaxial Cable (Cable TV), Fiber Optic Cable, LASERS or Radio Waves (Wireless Medium)
• We will see that Data needs to be transferred in the form of ELECTROMAGNETIC signals and The Transmission Medium should be capable of carrying these EM Signals

Transmission Media

PROTOCOL

• Set of Rules Governing Communication
• Represents an Agreement between communication devices
• Without Protocol, two devices may be connected but they will not be able to communicate

EXAMPLE: Consider the communication between two
individuals. They can only communicate provided they
both speak the same language.