Expt. No. 25: Connect Modem, Hub/Switches/Routers physically.

Modem: Modem is abbreviation for Modulator – Demodulator. Modems are used for data

transfer from one computer network to another computer network through telephone lines. The

computer network works in digital mode, while analog technology is used for carrying massages

across phone lines.

Fig1: Working of Modem.

Modulator converts information from digital mode to analog mode at the transmitting end

and demodulator converts the same from analog to digital at receiving end. The process of

converting analog signals of one computer network into digital signals of another computer

network so they can be processed by a receiving computer is referred to as digitizing. When an

analog facility is used for data communication between two digital devices called Data Terminal

Equipment (DTE), modems are used at each end. DTE can be a terminal or a computer.

HUB: Hub is a network hardware device for connecting multiple Ethernet devices together and

making them act as a single network segment. It has multiple input/output(I/O) ports, in which

a signal introduced at the input of any port appears at the output of every port except the original

incoming. A hub works at the physical layer (layer 1) of the OSI model. A repeater hub also

participates in collision detection, forwarding a jam signal to all ports if it detects a collision.

Fig2: Computer network

Physical layer function

A network hub is an unsophisticated device in comparison with a switch. As

a multiport repeater it works by repeating bits (symbols) received from one of its ports to all other

ports. It is aware of physical layer packets, that is it can detect their start (preamble), an idle line

(interpacket gap) and sense a collision which it also propagates by sending a jam signal. A

hub/repeater has no memory to store any data due to this; hubs can only run in half duplex mode.

Connecting multiple hubs

The need for hosts to be able to detect collisions limits the number of hubs and the total

size of a network built using hubs (a network built using switches does not have these limitations).

For 10 Mbit/s networks built using repeater hubs, up to five segments (four hubs) are allowed

between any two end stations For 10BASE-T networks, up to five segments and four repeaters are

allowed between any two hosts.

Fast Ethernet classes

100 Mbit/s hubs and repeaters come in two different speed grades: Class I delay the signal

for a maximum of 140 bit times and Class II hubs delay the signal for a maximum of 92 bit times.

Switches: On the surface, a switch looks much like a hub. Despite their similar appearance,

switches are far more efficient than hubs and are far more desirable for today’s network

environments.

As with a hub, computers connect to a switch via a length of twisted-pair cable. Multiple

switches are often interconnected to create larger networks. Despite their similarity in appearance

and their identical physical connections to computers, switches offer significant operational

advantages over hubs.

Fig3: Switches

Fig4: Working of switch.

Hub forwards data to all ports, regardless of whether the data is intended for the system

connected to the port. This arrangement is inefficient; however, it requires little intelligence on the

part of the hub, which is why hubs are inexpensive. Rather than forwarding data to all the

connected ports, a switch forwards data only to the port on which the destination system is

connected. It looks at the Media Access Control (MAC) addresses of the devices connected to it

to determine the correct port. A MAC address is a unique number that is stamped into every NIC.

By forwarding data only to the system to which the data is addressed, the switch decreases the

amount of traffic on each network link dramatically. In effect, the switch literally channels (or

switches, if you prefer) data between the ports.

Routers: Routers are small electronic devices that join multiple computer networks together via

either wired or wireless connections.

How Routers Work: In technical terms, a router is a Layer 3 network gateway device, meaning

that it connects two or more networks and that the router operates at the network layer of

the OSI model. Routers contain a processor (CPU), several kinds of digital memory, and input-

output (I/O) interfaces. They function as special-purpose computers, one that does not require a

keyboard or display.

Fig5: Routers

Types of Routers: There are several types of routers in the market.

1. Broadband Routers.

2. Wireless Routers.

3. Edge Router.

4. Subscriber Edge Router.

5. Inter-provider Border Router.

6. Core Router.

Expt. No. 26: Prepare and test crossover and straight cable, CAT5, CAT6

cables using crimping tools, splicer.

Procedure: To do these practical following steps should be done:

1. Start by stripping off about 2 inches of the plastic jacket off the end of the cable. Be very

careful at this point, as to not nick or cut into the wires, which are inside. Doing so could alter

the characteristics of your cable, or even worse render is useless. Check the wires, one more

time for nicks or cuts. If there are any, just whack the whole end off, and start over.

2. Spread the wires apart, but be sure to hold onto the base of the jacket with your other hand.

You do not want the wires to become untwisted down inside the jacket. Category 5 cable

must only have 1/2 of an inch of 'untwisted' wire at the end; otherwise it will be 'out of spec'.

At this point, you obviously have ALOT more than 1/2 of an inch of un-twisted wire.

3. You have 2 end jacks, which must be installed on your cable. If you are using a pre-made

cable, with one of the ends whacked off, you only have one end to install - the crossed over

end. Below are two diagrams, which show how you need to arrange the cables for each type

of cable end. Decide at this point which end you are making and examine the associated

picture below.

Diagram shows you how to prepare Cross wired connection

Diagram shows you how to prepare straight through wired connection

CAT 5: A good CAT5 termination provides a proper wire crimp. Also important, is not

unwinding the wires more than necessary. The wire diagram below is CAT5B.

Fig: network cable

Procedure:

1) Strip the cables Jacket back one full inch.

2) Untwist the wires back to within 1/8" of the jacket.

3) Arrange the wires in the order in which you want to crimp them, (568A, 568B, etc.).

4) Grasp the wires firmly, between your thumb and forefinger, flatten them, and even

wiggle them a bit, to take out the curliness, (concentrate your efforts on the bottom

1/2") the wires must lay flat and together, aligned as close as possible.

5) While holding the wires firmly, cut off the wires 1/2" from the cables jacket (Cut the

wires with some sharp wire strippers or even high quality scissors, avoid wire cutters

that flatten the ends of the wires insulating material, this makes stuffing the wires very

difficult.)

6) Stuff the wires into the connector, making sure the wires stay lined up. * The wires

should reach the end of the little tube they are in.

7) The jacket should go even with the end of the first indent; if possible, it's a strain relief

for the cable.

8) Insert it into the crimping tool, and Crimp it!

9) Repeat the process on the other end. For a straight through cable, use the same wiring.

For a "crossover" cable, wire one end 568A, and the other end 568B.

10) Use a cable tester to test for proper continuity.

CAT6:

Procedure:

Step 1 This procedure generally applies to Cat 6 RJ45 connectors. An alternate method is given

for connectors utilizing a "load bar".

Step 2 Cut the cable to the length needed. If you plan to use snagless boots, this would be a

good time to slide them on. Be sure the boots will be facing "out" towards the connector.

Step 3 Strip back the cable jacket approximately 1 inch. Use the cutter provided with the

crimping tool or strip by hand. Be careful not to nick the individual wires. Un-twist each of the 4

pairs and straighten each wire as much as possible between the fingers.

Step 4 Use the 568-B wiring scheme on both ends for a standard patch cable. For a crossover

type cable use the 568-B scheme on one end and the 568A on the other end.

Step 5 Bring all of the wires together as closely as possible. Hold the grouped (and sorted) wires

together tightly between the thumb, and the forefinger. Cut all of the wires at a perfect 90 degree

angle from the cable, 1/2 inch from the end of the cable jacket. Use a sharp cutting tool so as not

to "squash" the wire ends.

Step 6 With the connector pins facing up, carefully insert the wires into the connector. Apply a

moderate amount of force in order to properly seat the wires against the contacts in the

connector.

Expt. No. 28: write on CD/DVD, single/multi-session.

Single session Writing

Copying Files to a CD using the Live File System The following instructions explain how to

burn files to a CD on a computer running Windows 7 and have the CD remain in a state where

files can be burnt to it again on future occasions until the CD is full. This is known as Multi

Session CD Burning. The instructions also apply to burning to a DVD disc.

1) Insert a writable blank CD or DVD into the computer’s CD/DVD drive. On our modern

all in one style computers you will find the drive mounted vertically on the right hand

side of the computer.

2) A dialog box opens on the desktop listing various options, select Burn files to disc.

3) The Burn a Disc dialog box appears, note that the Like a USB flash drive option is

selected by default, enter a title for your disc and click Next, the disc will now be

formatted.

4) The AutoPlay dialog box appears, click on Open folder to view files.

5) A window appears displaying your available drives and network folder locations on the

left, your target CD is listed in this area as DVD RW Drive (D:) When your target DVD

RW Drive (D:) is selected an empty folder is displayed on the right into which you drag

or copy files to be burnt to your CD. Files are automatically burnt to your CD when

copied to this folder. You can also copy files to the CD by dragging them and dropping

them on to the DVD RW Drive (D:) icon in the left section.

6) When you have finished copying files to your disc it can be ejected from the drive by

pressing the drive’s eject button or by right clicking on DVD RW Drive (D:) in the left

hand pane and selecting Eject from the menu.

7) When you eject your CD, the system prompts you to wait until the session is closed

before ejecting. Closing the session enables the disc to be used on other computers.

8) Load the CD, as the CD is already formatted the AutoPlay dialog box appears, click on

Open folder to view files.

9) A window appears listing files on the CD, add new files to this list, they are automatically

burnt to the CD.

10) Files are easily deleted from the CD by clicking the filename and selecting Delete from

the drop down menu.

Multi-session Writing

1) When you want to start a multi-session disc in Nero 6 Burning ROM, use File =>

New... and select a DVD-ROM (ISO) compilation or other relevant compilation, select

the Multisession tab and select Start Multisession disc.

2) When you have added the relevant files press the burn button and don't select the Finalize

option.

3) When you want to add a new session to a multisession disc in Nero 6 Burning ROM,

use File => New... and select a DVD-ROM(ISO) compilation or other relevant

compilation, select the Multisession tab and select Continue Multisession disc.

4) In the Select Session window, choose the last session on the disc unless you want to

continue the multisession disc from an earlier session.

5) If the multisession disc was created by Nero, you might be asked whether to refresh the

compilation already on the disc. Choose the answer that is appropriate for your needs.

6) When you have added the relevant files press the burn button and don't select the Finalize

option.

7) You can continue doing this until the disc is full.

Expt. No. 29: Identify the fiber optic cable construction and connectivity.

An optical fiber cable, also known as fiber optic cable, is an assembly similar to

an electrical cable, but containing one or more optical fibers that are used to carry light. The optical

fiber elements are typically individually coated with plastic layers and contained in a protective

tube suitable for the environment where the cable will be deployed. Different types of cable are

used for different applications, for example long distance telecommunication, or providing a high-

speed data connection between different parts of a building.

Construction: Optical fiber consists of a core and a cladding layer, selected for total internal

reflection due to the difference in the refractive index between the two. In practical fibers, the

cladding is usually coated with a layer of acrylate polymer or polyimide. This coating protects the

fiber from damage but does not contribute to its optical waveguide properties. Individual coated

fibers (or fibers formed into ribbons or bundles) then have a tough resin buffer layer and/or core

tube(s) extruded around them to form the cable core. Several layers of protective sheathing,

depending on the application, are added to form the cable. Rigid fiber assemblies sometimes put

light-absorbing ("dark") glass between the fibers, to prevent light that leaks out of one fiber from

entering another. This reduces cross-talk between the fibers, or reduces flare in fiber bundle

imaging applications.

Fig1. Optic fiber internal structure

For indoor applications, the jacketed fiber is generally enclosed, with a bundle of flexible

fibrous polymer strength members like aramid (e.g. Twaron or Kevlar), in a lightweight plastic

cover to form a simple cable. Each end of the cable may be terminated with a specialized optical

fiber connector to allow it to be easily connected and disconnected from transmitting and receiving

equipment.

Capacity: In September 2012, NTT Japan demonstrated a single fiber cable that was able

to transfer 1 petabit per second (1015bits/s) over a distance of 50 kilometers. Optical cables transfer

data at the speed of light in glass. This is the speed of light in vacuum divided by the refractive

index of the glass used, typically around 180,000 to 200,000 km/s, resulting in 5.0 to 5.5

microseconds of latency per km. Thus the round-trip delay time for 1000 km is around 11

milliseconds.

Fig2: Optic fiber working

Working: Light travels down a fiber-optic cable by bouncing repeatedly off the walls.

Each tiny photon (particle of light) bounces down the pipe like a bobsleigh going down an ice run.

Now you might expect a beam of light, traveling in a clear glass pipe, simply to leak out of the

edges. But if light hits glass at a really shallow angle (less than 42 degrees), it reflects back in

again—as though the glass were really a mirror. This phenomenon is called total internal

reflection. It's one of the things that keeps light inside the pipe.

Expt. No.30: Identity Wi-Fi environment and its setup.

Connecting a Computer to the ScanSnap via a Wireless Access Point

Preparation

Connect the computer to a wireless access point that is to be used when connecting the computer

to the ScanSnap.

For a successful connection, the following information of the wireless access point is required:

1 Network name (SSID)

2 Security key (password)

In the window shown below, you can check or change the network the computer is connected to:

Connection Method

This method assumes that ScanSnap Manager is not installed on the computer that is to be connected to the

ScanSnap. Install ScanSnap Manager from the Setup DVD-ROM and follow the Wireless Network Setup

Wizard that appears after the installation is complete.

1. Click the [Setup Now] button.

2. Check the contents on the displayed window and click the [Next] button.

3. Click the [Yes] button.

4. Click the [OK] button.

5. Click the [Yes] button.

6. Check the contents on the displayed window and click the [OK] button.

7. Click the [No] button.

8. Click the [Finish] button.

Expt. No31: Identify wired network environment and its set up.

Wired network: connects devices to the Internet or other network using cables. The most

common wired networks use cables connected to Ethernet ports on the network router on one end

and to a computer or other device on the cable's opposite end.

Ethernet and wireless networks each have advantages and disadvantages; depending on your

needs, one may serve you better than the other. Wired networks provide users with plenty of

security and the ability to move lots of data very quickly. Wired networks are typically faster than

wireless networks, and they can be very affordable. However, the cost of Ethernet cable can add

up -- the more computers on your network and the farther apart they are, the more expensive your

network will be. In addition, unless you're building a new house and installing Ethernet cable in

the walls, you'll be able to see the cables running from place to place around your home, and wires

can greatly limit your mobility. A laptop owner, for example, won't be able to move around easily

if his computer is tethered to the wall.

There are three basic systems people use to set up wired networks. An Ethernet system

uses either a twisted copper-pair or coaxial-based transport system. The most commonly used

cable for Ethernet is a category 5 unshielded twisted pair (UTP) cable -- it's useful for businesses

who want to connect several devices together, such as computers and printers, but it's bulky and

expensive, making it less practical for home use. A phone line, on the other hand, simply uses

existing phone wiring found in most homes, and can provide fast services such as DSL.

Finally, broadband systems provide cable Internet and use the same type of coaxial cable that

gives us cable television.

Wired network Set up Steps:

Click on the START MENU and select CONTROL PANEL.

Select NETWORK AND INTERNET.

Select the NETWORK AND SHARING CENTER.

From the Tasks section on the left, select CHANGE ADAPTER SETTINGS.

Right-click the LOCAL AREA CONNECTION icon and select PROPERTIES.

From the User Access Control window, click CONTINUE.

Select INTERNET PROTOCOL VERSION 4 (TCP/IPv4), and then click

the PROPERTIES button.

Make sure OBTAIN AN IP ADDRESS AUTOMATICALLY and OBTAIN DNS SERVER

ADDRESS AUTOMATICALLY are selected.

Click the OK button to close the other open windows.

Restart the computer.

Expt. No.32: Identify Bluetooth based wireless mouse, keyboard and other

devices.

Bluetooth based Wireless Mouse:

There are two types of wireless mouse: Bluetooth, which connects directly to your

computer's Bluetooth receiver, and RF wireless, which connects to a receiver that you plug into

your computer.

For some computers that have Windows 8.1

Open Charm > Settings > Change PC settings > PC and devices > Bluetooth

For some computers that have Windows 7

Click Start > Control Panel > Hardware and Sound > Bluetooth Devices.

Bluetooth based Wireless keyboard:

A wireless keyboard is a computer keyboard that allows the user to communicate with

computers, tablets, or laptops with the help of radio frequency (RF), infrared (IR)

or Bluetooth technology. It is common for wireless keyboards available these days to be

accompanied by a wireless mouse.

Wireless keyboards based on infrared technology use light waves to transmit signals to

other infrared-enabled devices. But, in case of radio frequency technology, a wireless keyboard

communicates using signals which range from 27 MHz to up to 2.4 GHz. Most wireless keyboards

today work on 2.4 GHz radio frequency. Bluetooth is another technology that is being widely used

by wireless keyboards. These devices connect and communicate to their parent device via the

bluetooth protocol.

Bluetooth based Wireless Speaker:

All wireless speakers feature Bluetooth technology, enabling all Bluetooth devices to

stream their audio to the speakers without separate adapters or transmitters. Some models are

equipped with apt-X, a high performance low-latency audio codec for stereo Bluetooth audio.

Wireless speakers receive considerable criticism from high-end audiophiles because of the

potential for RF interference with other signal sources like cordless phones as well as for the

relatively low sound quality some models deliver.