2. DEFINITION of DATA
COMMUNICATION
“Data Communication is the exchange of Information
from one entity to the other using a Transmission
Medium”
3. LOCAL and REMOTE
Communication
LOCAL
– Communicating devices are present in the same
building or a similarly restricted geographical area.
– When the source and destination are in the same
network
4. Data Communication Definition
(Modified)
“Data Communication is the exchange of data (in the
form of 0’s and 1’s) between two devices
(computers) via some form of the transmission
medium.”
5. LOCAL and REMOTE
Communication
REMOTE
– Communicating devices are present farther apart.
– When the source and destination are in the different
network.
6. Data Communication System
For Data Communication to occur, communicating
devices must be a part of a system made up of some
specific kind of hardware and software. This system is
known as
“DATA COMMUNICATION SYSTEM”
7. Effectiveness of Data Comm.
System
Delivery (the data you send and it is received to the
destination)
Accuracy (what you send the same is received and
there is no error)
Timeliness (the data reach to the destination in good
time).
9. Components of a Data
Communication System
∗ A Data communication system is made up of 5
components:
∗ Message
∗ Sender
∗ Receiver
∗ Medium
∗ Protocol
10. Components of a Data
Communication System
Message:
It is the data which the source send to destination
∗ Sender:
a device which sends the data.
∗ Receiver:
a device which receive the data.
∗ Medium:
the path through which the data is traveling from sender to
receiver.
∗ Protocol:
Set of rules that govern communication or set of rules that makes
the communication both possible and efficient.
11. Transmission media
Guided media unguided media
Twisted pair cable optical fiber water, air, vacuum
coaxial cable
Shielded twisted pair Thick net Single mode
Unshielded twisted pair Thin net Multimode
12. Transmission Media
Medium Speed Cost
Twisted Wire 100bps-1000Mbps Low
Coaxial Cable 56Kbps-200Mbps Low
Fiber Optic Cable 500Kbps-10Gbps High
13. Wire Based Media
Twisted-pair cable
∗ Most common LAN cable
Called Cat5 or 100BaseT
∗ Four pairs of copper cable twisted
∗ May be shielded from interference
(polyester/aluminum)
∗ Speeds range from
1 Mbps to 1000 Mbps
∗ Twisted to remove the cross talk
∗ UTP and STP are types of twisted pair
14. Wire Based Media
Coaxial cable
∗ Also called coax
∗ Similar to cable TV wire
∗ One wire runs through cable
∗ Shielded from interference
∗ Speeds up to 200 Mbps
∗ Nearly obsolete
∗ Expensive than Twisted pair
15. Wire Based Media
Fiber-optic cable
∗ Data is transmitted with light
pulses (signals)
∗ Glass strand instead of cable
∗ Protected to interference
∗ Very secure
∗ Hard to work with
∗ Speeds up to
10 Gbps
17. Source
A device which generate data
Transmitter
Is a device which takes data from source and convert it into a form
that is transmutable over transmission media
Transmission system
Is the path available between source and destination and through
which the data can travel.
Receiver
Is a device that takes data from transmission system and convert it
into a form that is understandable by computer.
Destination
It is the final point of communication.
19. Key Data Communication Terminology
∗ Network: interconnected group of computers and communication
devices.
∗ Can share the resources
∗ Can share the data
∗ Node: a network-attached device that can send and receive the data.
E.g. Computer, router, Switch.
20. Key Data Communication Terminology
∗ Link: links are the path that connects adjacent nodes
∗ Path: end-to-end route within a network
∗ Circuit: the conduct over which data travels. Circuit is the path for
current flow. Circuit can be open or close. Open circuit means that there
is a break in the wire and current can not pass. A close circuit means
that circuit is complete and current can pass
21. Key Data Communication Terminology
∗ Packetizing: dividing messages into fixed-length packets prior to
transmission over a network’s communication media
∗ Routing: determining a message’s path from sending to receiving
nodes
∗ Router: router is the device that perform the function of routing and
switching
