Was one of the first applications of electrical technology. Today, in the age of fiber optics and satellite television, facsimile machines, internet and cellular phones, communication systems remains at the leading edge of electronic. Probable no other branch of electronics has as profound an effect on people’s everyday lives.

Movement of Information from a source through a channel to a receiver.

Initiates instruction to transmit data, instructions, or information.

Connects the sending device to the communications channel.

Connects the communications channel to the receiving device

Communication Channel

Accepts transmission of data, instructions, or information.

(Unguided Media) – Through Air

Amplitude Modulation ~ Kilohertz

Frequency Modulation (94.5) ~ Megahertz

Internet

Web

E-mail (Electronic Mail)

Instant Messaging

Chat Room

News Group

Internet Telephony

FTP

Web Folder

Video Conferencing

 Fax Machine

Can exist in a variety of forms – as numbers or text on pieces of paper, as bits and bytes stored in electronic memory, or as facts stored in a person’s mind.

-   Raw, Unprocessed

Short for Binary Digit, the smallest unit of information on a machine.

- Data that

(1)   Has been verified to be accurate and timely,

(2)   Is specific and organized for a purpose,

(3)   Is presented within a context that gives it meaning and relevance, and

(4)   That can lead to an increase in understanding and decrease in uncertainty.

- Processed

Voice, Message, Image, Sign, Data

-    The movement of information from one computer terminal to another computer terminal

- It is the process in which two or more computers or devices transfer data ,instruction and information

- Group of computers and devices connected via communications devices and transmission media

-  Used to share information and resource

Communication

are called “Stand alone computers”

- Created Network Infrastructure

- Network Standard

- OwnNetwork

1^st Internet

Internet Sharing

Network in limited geographical area such as home or office building

- Is a network that interconnects users with computer resources in a geographic area or region larger than that covered by even a large local area network (LAN) but smaller than the area covered by a wide area network (WAN)

- It is also used to mean the interconnection of several local area networks by bridging them with backbone lines. The latter usage is also sometimes referred to as a campus network.

 Network that covers large geographical area using types of media.

A ________________________ is the smallest and simplest type of network. It connect devices within the range of an individual and are no larger than about 10 meters (m). Because it operate in such limited areas of space, most are wireless and provide short-range connectivity with infrared technology.

- Reduce time and effort to

- Perform business task;

- Capture information and

- Centralize control over it, and then

- Disseminate this information rapidly, all in an effort to

- Cut costs, As part of this effort, a network should

- Grow incrementally as the company grows and either

- Centralize or decentralize computer systems to

-Support organizational goals, all of which join together to give

also called the source

usually called the transmitter path

occasionally called the sink

Data Terminal Equipment

- any device that acts as an origin of; or a destination of data

 - it is the transmitter or receiver of the information (ex. terminal or computer)

 - it is the source of data to be transmitted at one end and the sink that receives the data at the other   end

DCE

  - also known as DataCircuit-Terminating Equipment

  - it modulates and demodulates the signal. Converts the digital signal to analog and returns back from analog to digital at the other end to be receive by the DTE. (ex. modem)

  - the class of device that convey data overcommunication links to the edge of the network for attachment to DTE.

Any communication systems move information from a source to a destination through a channel. The information from the source will generally not be in forms that can travel through the channel, so a device called a transmitter will be employed to one end, and a receiver at the other end.

1. The DataTerminal Equipment (DTE) at point A.

   2. The interface between the DTE and the Data Circuit-Terminating Equipment (DCE or often called DataCommunications Equipment) at point A.

   3. The DCE at point A.

   4. The transmission channel between points A and B.

   5. The DCE at point B.

   6. The DCE - DTE interface at point B.

   7. The DTE at point B.

Two (2) -wire channel

Four(4) - wire channel

- it uses two wires only. One wire for sending(transmitting) and one wire for returning electrical signals (receiving).

Advantages: cheaper

Disadvantages: slower in speed than four wire

- it uses four wires. Two wires each for sending(transmitting) and two wires for returning electrical signal (receiving).

Advantages: faster

Disadvantages: more expensive

- transmission is in one direction only. With simplex operation, data

transmission is unidirectional.

Simplex lines are also called receive-only, transmit-only or one-way lines.

Advantages: cheaper

Disadvantages: no way of checking if data arrived at the other end

Example of Simplex

Transmission is in both direction but one at a time.Half-duplex line are also called two-way alternate or either-way lines.

Advantages: cheaper than full duplex

Disadvantages: slower than full duplex

Example of Half-Duplex (HDX)

transmission is in both direction and simultaneously, but they must be between the same two stations. Full duplex lines are also called two-way simultaneously or both-way lines

transmission is possible in both direction at the same timebut not between the same stations. One station is transmitting to a secondstation and receiving from a third station at the same time.

SerialTransmission

 Parallel Transmission

a network structure in which devices are connected to one cable (called BUS) or line running through the entire network.

Advantages: simple, Fast, and inexpensive to implement and

maintain.

Disadvantages: limited bandwidth capacity can't effectively support more devices as an organization grows.

Best for : Small networks w/ a limited number of devices.

connections between devices in a ring topology form a closed loop.

- travels around the loop in a single direction.

 - each devices uses a token communication protocol to receive

and pass on the data until it reaches the intended destination.

Advantages: can offer reliable signal strength and speed; more devices can be easily added without impacting band width.

Disadvantages: One device failure affects the whole network:

Best for : small - to medium - sized Local Arca Networks

Like bus topology, all devices in a network designed with star topology are connected to a central hub or switch

Advantages: additional devices are simply connected # the hub, which also makes it easy to manage and maintain. If a device fails, it won't affect the entire network.

Disadvantages: it the central hub fails, the entire network is affected. it can also be expensive to set up and challenging to maintain.

Best for: any network that requires multiple connection points due to its case of use and flexibility.

-         often described as a combination of bus and star topology.

-         consists of a central hub or switch as the root, which is connected to network segments as the "branches".

Advantages: supports scalability / continued high performance as a network grows.

Disadvantages: difficult to configure and maintain the network as it grows and become more complex.

Best for :Large networks complete comm requirements, such as corporate, offices ,hospitals, and. data center.

each device is connected to every other device in the network, creating a grid.

Advantages:  all those connections provide a number of benefits, including a wide range of paths for data transmission, enabling maximum speed and efficiency as well as multiple alternate paths in case of a fault with a device.

Disadvantages: The complexity and amount of equipment make mesh one of the most expensive types of topology as well as one of the most demanding to oversee.

Best for: Networks where reliable and continuous communication and access to data are of critical importance, such as in public safety, air transportation, and defense, industry.

-         refers to two devices that are linked to each other through a dedicated connection, such as a router and a workstation.

Advantages: Simple, inexpensive setup and past, secure, and reliable data transfer between the devices.

Disadvantages: Of limited use for most network needs.

Best for :Homes as well as environments where security is a top priority, such as emergency systems or military communications.

term for any topology that combines aspects of two or more of the network topology examples.

Advantages: enables you to custom- design a network for specific requirements, such as the star topology provides combined with the redundancy of mesh topology.

Disadvantages: can be expensive and time-consuming to set up and maintain

Best for:Large, complex networks with units or offices that have diff and specific needs. ... multinational companies, banks, and financial business, and higher education system.

configured all & wires in the same order on both ends of the cable.

same configuration is used at both ends of the cable.

W-green, green, W-orange, blue, W-blue, orange, W-brown, brown

W- orange, orange, W- green, blue, W-blue,green, W-brown, brown

-         configured 4 of the wires in the same order on each end.

-         The other 4 wires are crossed.

 directly connect two computers or two hubs wo the use of a nub or switch (peer to peer network connection).

-         is wired with each pin on one end of the cable connected, to the reversed pin on the other end.

-           used to connect the serial port of a computer to the serial port of a network switch so that you can configure the network switch.

  These cable are not used for network connectivity.