1. The document discusses the key components of data communications including the message or data being sent, the sender and receiver devices, the transmission medium, and protocols governing the communication. 2. It describes different transmission modes like simplex, half-duplex, and full-duplex data flow. 3. Various network topologies - mesh, star, bus, and ring - and common network devices like routers, modules, media converters, ONUs, and OLTs are outlined.

1. Overview of Network Components
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Data Communications

2. The word data refers to information presented in whatever form is
agreed upon by the parties creating and using the data. Data
communications are the exchange of data between two devices via
some form of transmission medium such as a wire cable or wireless.
What is Data Communications?
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3. Data Communications Components
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4. Data Communications Components
1- Message or Data
The Message is the information (data) to be communicated.
It can consist of text, number, pictures, sound or video or any combination of
these.
2- Sender
The sender is the device that sends the data message. It can be a computer,
workstation, telephone handset, video camera. And so on.
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5. Data Communications Components
3- Medium
The transmission medium is the physical path by which a message travels
from sender to receiver.
It can be twisted pair wire, coaxial cable, fiber optic or radio wave.
4- Receiver
The received is the device that receives the message.
It can be a computer, workstation, telephone handset, television, and so on
5- Protocol
A protocol is a set of rules that govern data communication. It represents an
agreement between the communicating devices. Without a protocol, two
devices may be connected but not communicating
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6. Transmission Mode (Data Flow)
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7. Simplex
Data in a simplex channel is always one way. Simplex channels are not often
used because it is not possible to send back error or control signals to the
transmit end.
Ex: - Radio
- TV
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8. Half-Duplex
A half-duplex channel can send and receive, but not at the same time. it is only
one end transmits at a time, the other end receives.
Ex: - ICOM
- Single way LAN
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9. Full-Duplex
Data can travel in both directions simultaneously. There is no need to switch from
transmit to receive mode like in half duplex
Ex: - Telephone
- Two-way LAN
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10. Type of Connections
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11. Network Topologies
Network topology is the study of the arrangement or mapping of the elements
(links, nodes, etc.) of a network, especially the physical (real) and logical (virtual)
interconnections between nodes.
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12. A Mesh topology
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13. A Star topology
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14. A Bus topology
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15. A Ring topology
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16. Router
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CISCO Routers
Mikrotik Router

17. Modules
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LC Patch Cord Cable
SFP Module

18. Media Convertor
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19. ONU and OLT
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ONU (Optical Network Unit)
OLT (Optical Line Termination)

20. Networking Protocols
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ICMP = Internet Control Message Protocol)
Although you may not have heard of ICMP,
you probably have heard of one of its
features: Ping
ICMP is a protocol that network devices (e.g. routers) use to generate error
messages when network issues are preventing IP packets from getting through.

21. Networking Protocols
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Telnet is a protocol, which is used on internet or Local Area Networks (LAN) to
connect with UNIX remote machine or router.
SSH (Secure Shell) Protocol, is a remote administration protocol that allows users to
access, control, and modify their remote servers over the internet.

22. End Devices
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End Devices, refer to computer, wireless router, wireless access point, server, smart
devices

23. The Network
A network is a set of devices (often referred to as nodes) connected by
communication links. A node can be a computer, printer, or any other device
capable of sending and/or receiving data generated by other nodes on the
network.
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24. The Internet
The Internet is a global system of interconnected computer networks that use the
standard Internet protocol suite (TCP/IP) to link several billion devices worldwide.
It is an international network of networks that consists of millions of private, public,
academic, business, and government packet switched networks, linked by a broad
array of electronic, wireless, and optical networking technologies
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