definition of project.docx

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Definition of project

The project PC to PC fiber optic communication deals with data transfer from one computer to

another. It uses C programming and the serial ports of the Computer. The ports are programmed

in C. MAX 232 is used to convert RS 232 logic to TTL logic and then an optical transmitter

circuit is used to transmit data via fiber optic cable.

The optical transmitter circuit has a LED which is matched as far the cable and MAX232 is

concerned. At the receiver an optical receiver circuit is used which receives data using a photo

diode and a MAX 232 again to convert TTL logic to RS 232 for the serial port at the receiving

end computer.

The desired baud rate can be set using the program. For transmitting data the programmed is

executed once and whatever is present at the serial port is sent to the other computer via the fiber

optic cable. At the receiver the program is executed to receive data on the serial port.

Data transfer is the need of todays world. Most of people can use internet for this . But presently

it would be time consuming. One can implement data transfer using wireless medium. But then it

will be a costly affair. The need, therefore, is felt for fiber optic communication which is cheaper

and more suitable for the task. It is cheaper than wireless medium and is prone to lesser loss ascompared to wireless medium.

Fiber optics has their own advantages; larger bandwidth, high speeds, only to name a few.

Therefore, we need to use optic fibers for the internet and LANs. This project can be used to chat

between two PCs. It can help transfer files at the desired speed between two PCs. If we expand

further, a network of PCs can be connected as it is observed in the cable net available today.

The conventional LAN cables can be replaced by fiber optic cables which can provide much

higher speeds and also larger information carrying capacity.

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Study of existing system

BLOCK DIAGRAM OF PC TO PC COMMUNICATION THROUGH OPTICAL FIBER

CABLE

The 9-pin serial port is the links interface to the local and remote computer. The overall design

should accomplish the following tasks:

a. Convert the local computer transmitted serial data into an optical signal, of appropriate signal

levels, that will be transmitted to a remote computer over a multimode fiber cable a distance of 1

meter for processing.

b. Convert optical singles received from the remote computer, via a separate fiber cable, to

RS232 signal levels that are to be relayed to the local computer for processing.

When complete, you should have a device that connects to your local computer via a serial cable

and to a remote computer via a pair of 1 meter fiber optic cables. The data sent from the local

computer will be converted from RS232 and sent over the fiber link using an LED. Data sent

from the remote computer will be detected with a standard photodiode and converted to an

RS232 signal so it can be processed by the local computer.

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TRANSMITTER

Data signals transmitted through pin3 of 9-pin D connector of RS-232 COM port are sent to

pin8 of MAX232 and it converts these RS-232 compatible levels of +9V or -9V to 0/5 volt TTL

levels as given in table.

The output of MAX232 drives the pnp transistor through a bias resistor of 1k ohm, to switch on

IR LEDS and also visible LED. Here actually when the output of MAX232 is 0V at that time

the pnp transistor will be conduct and the IRLED as well visible LED will glow. And when the

output of MAX232 is 5V at that time the pnp transistor will not conduct it is in cut-off region.

So, at that time the IRLED as well the visible LED will not glow.

We can use laser diodes and LEDs for the transmitter. Both have their own advantages and

disadvantages. But LEDs are more reliable and also cheap, so we will be using a LED.

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RECEVIER

A visible LED1 at pin 7 of MAX232 IC indicated that the signals are bagging received. Pin 7 is

also connected to pin 2 of pin 9 D connector used for the serial port in the PC, so that the data

may be read .The optical signals received by the photodiodes are in fact converted to electrical

pulses and both the pcs think that there is null modem cable connected between them.

The Receiver component serves two functions. First, it must sense or detect the light coupled out

of the fiber optic cable then convert the light into an electrical signal.

Secondly, it must demodulate this light to determine the identity of the binary data that it

represents. In total, it must detect light and then measure the relevant Information bearing light

wave parameters. A Receiver is generally designed with a Transmitter. Both are modules within

the same package. The very heart of the Receiver is the means for sensing the light output of the

fiber optic cable.

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STUDY OF PROPOSED SYSTEM

IMPROVEMENT OF OPTICAL FIBER COMMUNICATION SYSTEM

USING A PARALLEL INTERFACE CIRCUIT

A certain parallel interface circuit for an optical fiber system was designed and built. Suitable

software was built and tested. The performance of each part of the system was tested.

The final form of the circuit was tested individually. The complete system including the parallel

interface circuit was examined applying a case study. The performance of the system was good

within the acceptable experimental error.

The benefits got from interface personal computer with the environments are: high speed in

processing, low cost of (PC), high degree of reliability in (PC), availability of external storage

medium and availability of input and output devices.

There are three methods for connecting computer with the outside word: Serial interface, direct

interface, and parallel interface.

A serial communication is the technique that allows one computer to be connected to another

device by sending data through a transition media and receiving data on another and has a great

importance because of its flexibility. Various devices such as plotter, modem, and mouse and of

course a printer can be connected to the serial interface.

The common type of the direct interface is the plug in card, which fits into a free expansion slot

in the computer, and its main advantages are: low cost, high speed, and easily connected.

Finally, the parallel interface is quicker and cheaper. It works by sending data through collection

of eight wires at once, unlike the serial interface; parallel interface can send an entire byte of data

at once by using eight data wires.

For all these advantages of PC and optical fiber, recent work was concentrated on the

construction of parallel interface circuit for the use of optical fiber system.

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REQUIRMENT AND SPECIFICATION

HARDWARE REQUIREMENT:

Sr. No. COMPONENT QUANTITY

1. RS 232 cable 2

2. Optical fiber connector 4

3. Resistance 4.7k 2

4. Resistance47k 4

5. Resistance1.2k 4

6. Resistance1k 4

7. Resistance100k 2

8. Capacitor 1 12

9. LED 12

10. Transistor(PNP) 2

11. Connector(DB9) 2

12. MAX232 2

SOFTWAREREQUIREMENT:

Keil micro Version 3 (IDE)

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FEASIBILITY STUDY

Over the past two decades, the performance of computing systems has been increasing by

roughly 55% per year compounded, or roughly a factor of 10 improvements every 4 years.

Driven by Networks of workstations, the performance of LAN systems has been increasing at the

rate of roughly 60% per year compounded. For example, Ethernet technology has progressed

from 1 Mbit/s in the early 1980, to 1 Gbit/s in the late 1990. All projections indicate that the

trend will continue for the next 2 decades. Hence, within a decade 100Gbit/s LAN technology is

expected Optical fiber has been the preferred cabling technology for certain building and campus

network LAN backbones.

ECONOMIC FEASIBILITYLY

However, choosing to use optical fiber in a network over other cabling options may present

significant advantages in its inherent ability to handle data at higher speeds. Decreasing costs of

optical fiber components compared to the increasing electronic costs of carrying Gigabit

Ethernet over Cat 5 or Cat 5E UTP copper cabling has also accelerated themigration to optical

fiber LAN.

OPERATIONAL FEASIBILITY

This provides an introduction to Fiber Optic Technology, Fiber-Optic LANnetwork and Gigabit

Technology. The main objective of the is to conduct afeasibility study of performing a migration

to fiber for the Software Metrics Laboratory (SML) Local Area Network (LAN) in Ingersoll

Hall, (room 158), in Naval PostgraduateSchool (NPS). The intention of the fiber optic LAN is to

replace the traditional coppercable LAN in the SML.

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TECHNICAL FEASIBILITY

The demands for Internet access to WEB based application as well as integrated

multimedia applications (voice/data/video) have fueled the need for higher bandwidth

networks. Rapid advances in microelectronics and optical networking technologies are

enabling the increased bandwidth capacity.

As an academic institution, we would want to consider higher bandwidth (ie 1 or

10 Gb/s) LAN technologies today in order to ensure that our network has the capacity

and performance required to allow a graceful and rapid migration to these new

technologies when required.

Fig : This graph show the loss in the optical fiber when distance is large

The above graph show the loss when the optical fiber cable is very large usually there is 2db of

loss per kilometer in the optical fiber cable.

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SCOPE

In the very beginning we have tried to send ASCII characters between two computers. But as we

proceeded further we realized that this project can help transfer files at desired speed between

two PCs. If we expand the idea a bit further, a network of PCs can be connected, like in the cable

net available today. The Conventional LAN cables can be replaced by fiber optic cables which

can provide much higher speeds and also larger information carrying capacity.

There is no question that fiber optic communication is our future. Fiber optic communication

industry has been enjoying amazing growth for over 15 years. These are driven by both

technology advance and market demand. There are some obvious trends in the development of

new technology and market. All-optical network has been a top topic in fiber optic

communication industry for over a decade now. Its ultimate goal is to process all signals in the

optical domain without any conversion and controlling to electrical domain at all.

At least for now, most signal routing, processing and switching happens in the electrical domain.

Optical signals have to be converted to electrical signal first, and then the electrical signals are

processed, routed and switched to their final destination. After the processing, routing and

switching, the electrical signals are then converted back to optical signals which are then

transmitted over long distances. This process is called the O-E-O process. However, many

obstacles still lie in our way to make all-optical network a reality. Some functions such as

reading headers on the optical signals, switching the optical signal on the fly based on the header

content and real-time wavelength switching are just a few of the serious challenges that need to

be solved before we can have a true all-optical network.

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REFERENCE

Let us c by Yashwant Kanitkar

www.howstuffworks.com

www.RS232 Tutorial on Data Interface and cables.htm

www.MAX232N Bus-Line Transceivers (MAX232CPE).htm

www. fiberopticcable tutorial .htm

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