Project Report Final PrintNEW

INTERACTIVE VOICE RESPONSE SYSTEM A project submitted in partial fulfillment for the requirement of the award of the degree of

Bachelor of Engineering

In

Electronics & Communication

By:

Sam Abhinav Kullu (2k7/EC/690)

Sandeep Kumar (2k7/EC/691)

Sudhanshu Bhasin (2k7/EC/699)

Sujeet Kumar (2k7/EC/700)

Under the guidance of

Mrs. Priyanka Jain

Assistant Professor

Department of Electronics & Communication Engineering

Delhi College of Engineering

University Of Delhi

Year 2011

DECLARATION

We hereby declare that the work which is being presented in the major project entitled "Interactive Voice Response System" in the partial fulfillment for the award of degree of Bachelor of Engineering in Electronics & Communication submitted to Delhi College Of Engineering, University of Delhi, is an authentic record of our own work carried out under the supervision of Mrs. Priyanka Jain, Assistant Professor, Department Of Electronics & Communication, Delhi College Of Engineering, University of Delhi. We have not submitted the matter represented in this dissertation for the award of any other degree or diploma or any other purpose whatever.





CERTIFICATE It is to certify that dissertation, entitled " Interactive Voice Response System " submitted by the following students in partial

fulfillment of the requirements of the award of the degree of

bachelor of engineering in electronics and communication,

submitted in the department of electronics and communication

engineering, Delhi college of engineering, Delhi, is an authentic

record of student's own work carried out by them under the guidance

and supervision.





It is also certified that this dissertation has not been submitted for the award of any other degree or diploma in any other college/university.

Mrs. Priyanka Jain

Assistant Professor

Electronics & Comm. Engineering

Department

Delhi College of Engineering

4

Acknowledgement

It is great pleasure to have the opportunity to extent our heartiest felt gratitude to everybody who helped us throughout the course of this dissertation. It is distinct pleasure to impress our deep sense of gratitude and indebtedness to our learned supervisor Assistant Professor Mrs Priyanka Jain, Electronics & Communication Deptt. submitted to Delhi College of Engineering, University of Delhi for their invaluable guidance, encouragement and patient review. Their continuous inspiration only had made us complete this dissertation. We are also thankful to our friends and classmates for their unconditional support and motivation for this dissertation.

5

Table of Contents

Chapter 1 Introduction .............................................................................................. 3

1.1 Description....................................................................................................... 4

1.2 Objective .....……………………………………………………………...…....6

1.3 Layout of chapters... …………………………………………………………...6

Chapter 2 Literature Survey.………………………………………………………..7

2.1 History and technology background.............................................................. 8

2.2 Typical Uses .............................................................................. ……………9

2.3 Potential Uses ………………………………………………………………..11

2.4 Criticism …………………………………………….……………………….13

Chapter 3 General Overview of IVRS System……………………………………15

3.1 What is IVRS?......................................................................................16

3.2 Technology used……………………………………………………………..17

3.3 Block diagram………………………………………………………………..20

3.4 Components…………...……………………………….……………….…....21

3.5 Explanation………… ………………………………………………….…..21

3.5.1 Telephone …………………….……………………………………..….21

3.5.2 DTMF signaling.….……………………………………………………...23

3.5.3 Ring detector………..……………………………………………….…...25

3.5.4 ON-OFF hook stimulator…….. ……………………………………..….26

3.5.5 Microcontroller.……………………………………………………….....26

3.5.6 Voltage convertor………..………………………………………………27

3.5.7 PC serial port....……………………………………………………….....27

3.5.8 Interfacing circuit………..……………………………………………….28

3.6 Hardware describtion..……………………………………………………..…28

3.6.1 Microcontroller.…………………….……………………………………28

3.6.2 DTMF decoder.…………………………………………………………...30

6

3.5.3 Ring detector………..………………………………...……………….…..56

3.5.4 ON-OFF hook stimulator…….. ……………………...………………..….28

Chapter 4 Circuit Explanation…………………………………………………….…41

4.1 Circuit diagram…………………………………………………………………42

4.2 Circuit operation……………………………………………………......………42

4.2.1 Telephone ring sensor………………………………………………...……44

4.2.2 ON-OFF hook stimulator ……………………………………………….....48

4.2.3 PC serial port ………………………………………………...…………….51

Chapter 5 Software description……………………………………………….….…..56

5.1 Visual basic 6.0 ……….………………………………….…………...…….…57

5.2 Visual basic (serial communication)…..………………………….…………….58

5.2.1 Introduction…………………….……………………………………….....59

5.2.2 Communication control……………………….……………………………60

Chapter 6 Methodology……………………………..……..………………................64

6.1 Microcontroller ………………………………………………..…………….....65

6.1 Visual basic ………………………………………………..………….…….....66

Chapter 7 Conclusions And Future Enhacement…………………………...……..70

. 7.1 Conclusions …………………………………………………………….………71

7.2 Future Enhacement …………………………………………………….……....71

Appendices………………………………………………………………..………..….72

Source Code………………………………………………………….……………..….72

References……………...……………………..………………………………….…….85

7

CHAPTER 1

INTRODUCTION

8

1.1 DESCRIPTION

Now-a-days every inst i tu t ion needs automat ion. As a par t o f

co l lege automat ion, we have decided to do a pro ject “Voice

Interact ive System for Col lege Automat ion” . Our pro ject a l lows

the user to know the student ’s rank in any exam through the

te lephone l ine wi thout in ter ference o f the col lege author i ty . In

the hardware side embedded system has been used. A 40 p in

microcontro l ler 89C2051 is used because o f i t s compat ib i l i ty wi th

our hardware. This microcontro l ler contro ls the whole hardware.

Telephone l ine is used for communicat ion purpose. Visual Basic

has been used for so ftware programming.

In our Project a 20 p in Microcontro l ler AT89C2051 is used to

contro l the whole hardware. The Microcontro l ler senses the

DTMF signal through the DTMF decoder IC MT8870 and i t

responds according to the decoded signal . The c i rcui t has an

inbui l t Phone Ring sensor c i rcu i t and the system wil l take over

the phone automat ical ly using a 12 V relay. The microcontro l ler

wi l l receive the s ignal f rom the distance te lephone and i t decodes

the s ignal and fetches the data f rom the PC through the ser ia l

9

port , based on the te lephone s ignal , and sends the data through

the te lephone l ine.

Fig. 1.1 IVR SYSTEM

10

1.2 OBJECTIVE

The object ive o f our pro ject is to know the student’s rank in an

entrance exam qu ick ly through the te lephone wi thout the

in ter ference o f co l lege author i ty . By d ial ing the provided

te lephone number, one can d ig up the in format ion o f the student .

One o f the advantages is the t ime spending for col lege o f f ic ia ls

in answer ing phone cal ls f rom outs iders wi l l be reduced.

1.3 LAYOUT OF CHAPTERS

In next chapters, we give review of the IVR system, a detailed introduction to the

technology, Hardware used and show its distinctiveness from other softwares. This

is followed by a description of the proposed methodology for developing IVR

SYSTEM.

11

CHAPTER 2

LITERATURE SURVEY

12

2.1 HISTORY

The blueprint for IVR began in 1941, when Bell System developed a new tone

dialing methodology. Bell unveiled the first telephone that could dial area codes

using Dual Tone Multi Frequency DTMF technology at the Seattle World Fair in

1962. DTMF telephones enabled the use of inband signaling.

Despite the fact that more companies began using the system in the 1970s to

automate tasks in call centers, the technology was still costly and complicated

which made for low market penetration. However, by the 1980s a number of new

competitors entered the market and uptake of IVR technology started to increase.

When call centers began to migrate to multimedia contact centers in the late 90's,

companies began to invest in web-enablement and Computer Telephony

Integration (CTI) with IVR systems. IVR became vital for call centers deploying

universal queuing and routing solutions and acted as an agent which collected

customer data to enable intelligent routing decisions.

13

Having remained technologically static since its development in the 1980s, speech

recognition started to become more common and cheaper to deploy. This was due

to increased Computer Processing Power and the migration of Speech applications

from propriety code to the VXML standard. The introduction of the VXML

standard also simplified the integration process between IVR systems and any back

end hosts.

2.2 TYPICAL USES

• IVR systems are typically used to service high call volumes, reduce cost and

improve the customer experience. Examples of typical IVR applications are:

telephone banking, televoting, and credit card transactions. Large companies

use IVR services to extend the business hours of operation.

• Call centers use IVR systems to identify and segment callers. The ability to

identify customers allows the ability to tailor services according to the

customer profile. It also allows the option of choosing automated services.

Information can be fed to the caller allowing choices such as: wait in the

queue, choose an automated service, or request a callback (at a suitable time

and telephone number). The use of computer telephony integration (CTI)

will allow the IVR system to look up the caller line identification (CLI) on a

network database and identify the caller. This is currently accurate for about

14

80% of inbound calls. In the cases where CLI is withheld or unavailable, the

caller can be asked to identify themselves by other methods such as a PIN or

password. The use of DNIS will ensure that the correct application and

language is executed by the IVR system.

• The use of IVR and voice automation enables a company to improve its

customer service and lower its costs, due to the fact that callers’ queries can

be resolved without the cost of a live agent who, in turn, can be directed to

deal with specific areas of the service. If the caller does not find the

information they need, or require further assistance, the call is then

transferred to an agent who can deal with them directly through CTI

integration. This makes for a more efficient system in which agents have

more time to deal with complex interactions, for example, customer

retention, up selling, cross selling and issue resolution. This way, the

customer is more likely to be satisfied with a personalised service and the

interaction is likely to be more fulfilling and rewarding for the agent, as

opposed to dealing with basic enquiries that require yes/no responses, such

as obtaining customer details. Employee satisfaction is important in the

telecommunications industry due to the fast turnover of staff, IVR is

therefore one way of retaining a workforce and allowing them to do a more

effective job.

15

• IVR also enables customer prioritisation. In a system whereby individual

customers may have a different status, for example, a bronze, gold or

platinum card holder, the service will automatically prioritise the individuals

call and, in the case of a platinum card holder, move them to the front of the

calling queue.

2.3 POTENTIAL USES

• Voice-Activated Dialers

(VAD) Voice-activated IVR systems are now used to replace the

switchboard or PABX (Private Automatic Branch eXchange) operators and

are used in many hospitals and large businesses to reduce the caller waiting

time. An additional function is the ability to allow external callers to page

hospital staff and transfer the inbound call to the paged person.

• Entertainment and Information

The largest installed IVR platforms are used for applications such as tele-

voting on TV game shows such as Pop Idol and Big Brother which can

generate enormous call spikes. Often the network provider will have to

deploy Call gapping in the Public network to prevent Network overload.

The following are some of the more common uses of an IVR:

16

o Mobile (Pay as you go Top up)

o Telephone Banking (Balance, payments, and transfers)

o Mobile Purchases (particularly for mobile content, such as ringtones and

logos)

o Caller identification and routing

o Order Placements (Credit Card Payments)

o Airline (Ticket booking, Flight arrivals, Flight departures, Checkin)

o Adult entertainment (Dating, Chat line etc)

o Weather forecasts

• Clinical Trials

IVR systems are used by pharmaceutical companies and contract research

organizations to conduct clinical trials and manage the large volumes of data

generated. The caller will respond to questions in their preferred language

and their responses will be logged into a database and possibly recorded at

the same time to confirm authenticity. Applications include patient

randomization and drug supply management.

• Outbound Calling

17

IVR systems can be used for outbound calls, as IVR systems are more

intelligent than Dialler systems, they can recognise different line conditions.

o RNA Ring No Answer

o Answered by Voicemail or Answering machine (In this circumstances they

can leave a message)

o Fax Tone (IVR can leave a Fax Message based upon a TIFF Image)

o Answer (IVR can tell the customer who is calling and ask them to wait for

an agent)

o Recognise Divert messages and abandon call.

IVR uses Call Progress Detection to monitor Line conditions, and report to

the IVR Database.

2.4 CRITICISM

IVR is sometimes criticized as being unhelpful and difficult to use due to poor

design and lack of appreciation of the caller's needs.[4] Some callers object to

providing voice response to an automated system and prefer speaking with a

human respondent. A properly designed IVR application should provide the caller's

needs promptly and with a minimum of complexity.[neutrality disputed] However some

18

companies use IVR to reduce operational costs and will not offer similar services

using agents. Such services tend to frustrate customers who feel that their right to

speak to an agent is being restricted. Companies that deploy such services tend to

ignore customer opinion. Such services are used in debt recovery and giveaways

(Such as Concert tickets, Satellite/Cable Receivers etc).

19

CHAPTER 3

GENERAL OVERVIEW

OF

IVRS

20

3.1 What is IVR System ?

Interactive Voice Response (IVR ) system is an interactive technology that allows

a computer to detect voice and keypad inputs. IVR technology is used extensively

in telecommunications, but is also being introduced into automobile systems for

hands-free operation. Current deployment in automobiles revolves around satellite

navigation, audio and mobile phone systems. In telecommunications, IVR allows

customers to access a company’s database via a telephone touchtone keypad or by

speech recognition, after which they can service their own enquiries by following

the instructions. IVR systems can respond with pre-recorded or dynamically

generated audio to further direct users on how to proceed. IVR systems can be used

to control almost any function where the interface can be broken down into a series

of simple menu choices. In telecommunications applications, such as customer

support lines, IVR systems generally scale well to handle large call volumes.

It has become common in industries that have recently entered the telecom

industry to refer to an Automated Attendant as an IVR. The terms Automated

Attendant and IVR are distinct and mean different things to traditional telecom

professionals, whereas emerging telephony and VoIP professionals often use the

21

term IVR as a catch-all to signify any kind of telephony menu, even a basic

automated attendant.

3.2 Technologies Used

DTMF signals (entered from the telephone keypad) and natural language speech

recognition interpret the caller's response to voice prompts.

Other technologies include the ability to speak complex and dynamic information

such as an e-mail, news report or weather information using Text-To-Speech

(TTS). TTS is computer generated synthesized speech that is no longer the robotic

voice generally associated with computers. Real voices create the speech in tiny

fragments that are spliced together (concatenated) before being played to the caller.

An IVR can be utilized in several different ways:

1. Equipment installed on the customer premise

2. Equipment installed in the PSTN (Public Switched Telephone Network)

3. Application service provider (ASP).

4. Hosted IVR

A simple voicemail system is different from IVR in that it is person to person

whereas an IVR is person to computer. IVR voiceforms can be used to provide a

22

more complex voicemail experience to the caller. For example, the IVR could ask

if the caller wishes to hear, edit, forward or remove a message that was just

recorded.

An automatic call distributor (ACD) is often the first point of contact when calling

many larger businesses. An ACD uses digital storage devices to play greetings or

announcements, but typically routes a caller without prompting for input. An IVR

can play announcements and request an input from the caller. This information can

be used to profile the caller and route the call to an agent with a particular skillset.

(A skillset is a function applied to a group of call-center agents with a particular

skill.)

Interactive voice response can be used to front-end a call center operation by

identifying the needs of the caller. Information can be obtained from the caller

such as account numbers. Answers to simple questions such as account balances or

pre-recorded information can be provided without operator intervention. Account

numbers from the IVR are often compared to caller ID data for security reasons

and additional IVR responses are required if the caller ID data does not match the

account record.

IVR call flows are created in a variety of ways. A traditional IVR depended upon

proprietary programming or scripting languages, whereas modern IVR applications

23

are structured similar to WWW pages, using VoiceXML[1], CCXML[2], SRGS[3],

SALT or T-XML languages. The ability to use XML developed applications

allows a Web server to act as an application server, freeing the developer to focus

on the call flow. It was widely believed that developers would no longer require

specialized programming skills, however this has been proven to be misguided as

IVR applications need to understand the human reaction to the application

dialogue. This is the difference between a good user experience and IVR hell.

Higher level IVR development tools are available in recent years to further

simplify the application development process. A call flow diagram can be drawn

with a GUI tool and the application code (VoiceXML or SALT) can be

automatically generated. In addition, these tools normally provide extension

mechanisms for software integration, such as HTTP interface to web site and Java

interface for connecting to a database.

In telecommunications, an audio response unit (ARU) is a device that provides

synthesized voice responses to touch-tone keypresses (DTMF) by processing calls

based on (a) the call-originator input, (b) information received from a database,

and (c) information in the incoming call, such as the time of day.

ARUs increase the number of information calls handled and to provide consistent

quality in information retrieval.

24

3.3 BLOCK DIAGRAM

DTMF DECODER

RING DETECTOR

ON/OFF HOOK

SIMULATOR

MICROCONTROLLER

INTERFACING CIRCUIT

VOLTAGECONVERTER

PC SERIALPORT

PC SPEAKER

OUT

PERSONALCOMPUTER

TELEPHONE LINE

Figure 3 .1 Bas i c B lock D iagram

25

3.4 COMPONENTS

The above Block d iagram consist o f fo l lowing Blocks

1. Telephone sect ion

2. DTMF Decoder

3. Ring Detector

4. ON/OFF hook Simulator

5. Microcontro l ler

6. Voltage converter

7. PC Seria l Por t

8. Personal Computer (PC)

3.5 EXPLANATION

3.5.1. TELEPHONE

Invented by Bel l and h is assistant , Thomas A. Watson, the

te lephone marked a s igni f icant development in the history o f

e lectr ical communicat ion systems. In the ear l iest magneto-

telephone o f 1876, the speaker’s voice was converted into

electr ical energy pat te rns that could be send over reasonably long

d istances over wi res to a receiver, which would convert these

energy pat terns back into the or ig inal sound waves for the

l i stener.

26

Outgoing Cal l

The dial pad, a lso cal led keypad or touchtone pad, is used to d ia l

te lephone numbers as wel l as in teract wi th voice processing

system such as a voice mai l and interact ive voice response ( IVR).

The address s ignal ing for an outgoing cal l can be accompl ished

by 3 d i f ferent methods: pulse d ial ( rotary) , real tone mul t ip le

f requency (DTMF), or mult i frequency (MF)

Mult i -Frequency (MF):

I t however became more popular wi th the in t roduct ion o f dual

tone mul t ip le frequency (DTMF) mode o f d ia l ing. Single chip

DTMF encoders/decoders are avai lable today, which make the

designing such systems easy and re l iable

Mult i - f requency signal ing is s imi la r to DTMF and is used on

t runk c i rcui t , pay te lephones. Combinat ion o f two tones is used to

t ransmit s ignal ing in format ion, MF and DTMF signals are more

rel iable and considerably faster than pulse d ial . In both methods,

d ig i ts are t ransmit ted at the rate of about 7 d igi ts per second.

27

Incoming cal l

When a te lephone set i s cal led, the local exchange generates a

h igh r ing vol tage o f about 90-105Vol ts AC wi th a f requency o f

20Hz superimposed over the minus ( - ) 48Vol t DC. A capaci tor in

the phone passes the AC but b lock DC. Upon detect ing the AC

vol tage, the phone provides an aud ib le s ignal that a l tos the user

o f an incoming ca l l . Each te lephone set provide a ringer

equ iva lent number (REN) as def ined wi th in FCC part 68 and EIA

RS-470.The REN is used to ensure that the local exchange can

provide the correct amount o f power requi red to r ing the

te lephone. I t descr ibes the frequency range, power range, and

b ias vo l tage range o f the te lephone set . When the phone is

answered, DC cur rent begins to f low in the loop. The local

exchange the current f low and removes the super imposed r ing

vol tage. The -48Vol ts DC that i s a lways on the l ine operates the

te lephone when i t is be ing used.

3 .5.2 DTMF SIGNALING

DTMF stands for Dual Tone Mul t ip le Frequency. I t i s a tone

consist ing o f two frequencies super imposed. Indiv idual

f requencies are chosen such that i t i s easy to design f i l ters and

easy to t ransmit the tones through a te lephone l ine having

bandwidth o f approximate ly 3.5 kHz. DTMF was not intended to

be used for data t ransfer , i t was meant to be used for sending the

28

contro l s ignals along the te lephone l ine. Wi th standard decoders

i t is possib le to send 10 beeps per second i .e. , f ive b i ts per

second. DTMF standard speci f ies 50ms tones and 600ms durat ion

between two successive tones.

Tab le.3 .2 DTMF Keypad Frequencies

Generat ing DTMF

DTMF signals can be generated through dedicated ICs or by using

RC networks connected to a microprocessor. MT8880 is an

example o f a dedicated IC. But gett ing the lat ter method work is

a b i t d i f f icu l t i f h igh accuracy is needed. The crystal f requency

needs to be sacr i f i ced for a non standard cyc le length. Hence th is

1209 Hz 1336 Hz 1477 Hz 1633 Hz

697 Hz 1 2 3 A

770 Hz 4 5 6 B

852 Hz 7 8 9 C

941 Hz * 0 # D

29

method is used for simple appl icat ions. Most o f ten, a PIC micro

cou ld be used for the above purpose.

Decoding DTMF

Detect ing DTMF with sat is factory prec is ion is a hard th ing.

Of ten, a ded icated IC such as MT8870 is used for this purpose. I t

uses two 6 th order band-pass f i l ters using swi tched capaci tor

f i l ters and i t suppresses any harmonics. Hence they can produce

pret ty good s ine waves from d istorted input . Hence i t i s

prefer red. Again microprocessors can a lso be used, but the ir

app l icat ion is l imi ted.

3.5.3. RING DETECTOR:

I t is used to detect the r ing s ignal f rom the te lephone l ine. I t

g ives out a logica l output to the microcontro l ler . An optocoupler

MCT2E is used as r ing detector .

I f r ing is present – logic 0

E lse- logic 1

Normal t ime vol tage in te lephone l ine=48V d.c

OFF hook vol tage-12V d.c

Ring signal vo l tage-75V a.c

30

3.5.4. ON–OFF HOOK SIMULATOR

I t i s used to p ickup the te lephone elect ronical ly . A 12 vol t d .c

s ignal i s obta ined by p lacing a resistor across the te lephone l ine.

I t i s used to detect whether the Hand set i s in ON hook condi t ion

or OFF hook cond i t ion so as to send the in format ion to the

microcontro l ler . A 12 V relay is used for the purpose.

3.5.5. MICROCONTROLLER

A by-product o f microprocessor development was the

microcontro l ler . The same fabr icat ion techniques and

programming concepts that make possib le the genera l-purpose

microprocessor also y ie lded the microcontro l ler .

Micro contro l lers are not as wel l known to the general publ ic , or

to many in the technica l communi ty , as are the more g lamorous

microprocessor. The publ ic i s, however, very wel l aware that

“something” is responsib le for a l l o f the smart VCRs, c lock

radios, washers and dryers, v ideo games, te lephones, microwaves,

TVs, automobi les, toys, vending machines, cop iers, e levators,

i rons, and a myriad o f other ar t ic les that are in tel l igent and

“programmable”. Companies are also aware that being

31

compet i t ive in th is age o f the microchip requires the ir products,

or the machinery they use to make those products, to have some

“smar ts” .

3.5.6. VOLTAGE CONVERTER

This is used to convert TTL logic vol tage in to RS232 vol tage.

TTL Logic: log ic 1= 5v

log ic 0= GND

RS232 : log ic 1= +9v

log ic 0= -9v

IC MAX232 is used as vol tage converter . An external crystal

osci l la tor i s used for i t s operat ion.

3.5.7. PC SERIAL PORT

This port i s used to get data from microcontro l ler to personal

computer in ser ia l manner. Al l IBM PC and compat ib le computers

are typ ical ly equ ipped wi th two ser ia l por ts and one paral le l port .

Al though these two types o f ports are used for communicat ing

wi th external devices, they work in d i f ferent ways.

32

A para l le l por t sends and receives data eight b i ts at a t ime over 8

separate wi res. This al lows data to be t ransfer red very quick ly;

however, the cable requi red is more bulky because of the number

o f ind iv idual wi res i t must conta in. Paral le l por ts are typ ical ly

used to connect a PC to a pr inter and are rarely used for much

else. A ser ia l port sends and receives data one b i t a t a t ime over

one wire. Whi le i t takes e ight t imes as long to t ransfer each byte

o f data th is way, only a few wires are requi red.

In fact , two-way ( fu l l duplex) communicat ions is possib le wi th

only three separate wi res - one to send, one to receive, and a

common signal ground wire.

3.5.8. INTERFACING CIRCUIT

This is used to in ter face the audio signal f rom the computer to

the te lephone l ine

3.6 HARDWARE DESCRIPTION

3.6.1 MICROCONTROLLER

The AT89C2051 is a low-vo l tage, h igh-per formance CMOS 8-bi t

microcomputer wi th 2 Kbytes o f Flash programmable and erasable

read only memory (PEROM). The device is manufactured using

33

Atmel ’s h igh densi ty nonvolat i le memory technology and is

compat ib le wi th the industry standard MCS-51 instruct ion set and

p inout . By combining a versat i le 8-b i t CPU wi th Flash on a

monol i th ic ch ip, the Atmel AT89C2051 is a powerfu l

microcomputer which provides a h ighly f lex ib le and cost

e f fect ive so lu t ion to many embedded contro l appl icat ions.

The AT89C2051 prov ides the fo l lowing standard features: 2

Kbytes o f Flash, 128 bytes o f RAM, 15 I /O l ines, two 16-bi t

t imer/counters, f ive vector two- level in terrupt archi tecture, a fu l l

duplex ser ia l por t , a precis ion analog comparator , on-chip

osci l la tor and c lock c i rcu i t ry .

In addi t ion, the AT89C2051 is designed wi th s tat ic logic for

operat ion down to zero f requency and supports two software

se lectable power saving modes. The Id le Mode stops the CPU

whi le a l lowing the RAM, t imer/counters, ser ia l por t and interrupt

system to cont inue funct ioning. The Power Down Mode saves the

RAM contents but f reezes the osci l lator d isabl ing al l o ther chip

funct ions unt i l the next hardware reset .

3.6.1.1 Pin Conf igura t ion

The microcontro l ler AT89C2051 is avai lable in 20 p in Dual

In l ine Package (DIP).

34

Figure.3.5 Pin d iagram of AT89C2051

3.6.2 DTMF Decoder

The MT8870 is a s ingle chip DTMF receiver in corpora t ing

swi tched capaci tor f i l ter technology and an advanced d ig i ta l

count ing / averaging algor i thm for per iod measurement. The

funct ional b lock d iagram of MT8870 is shown in the below f igure

depic ts the in ternal work ing of this device.

35

Figure.3.8 Funct ional d iagram of IC MT8870

The DTMF signal i s f i rs t buf fered by input op-amp that a l lows

adjustment gain and choice o f input conf igurat ion. The input

stage is fo l lowed by a low pass RC act ive f i l ter , which per forms

ant a l ias ing funct ion. Dia l tone at 350 and 440Hz is then rejected

by a 3r d o rder swi tched capaci tor notch f i l ter . The s ignal is st i l l

in i t s indiv idual components by two 6t h order swi tched capaci tor

band pass f i l ter . Each component smoothed by an output f i l ter

and squared by a hard l imi t ing comparator. The two resul t ing

rectangular waveforms are then appl ied to a d ig i tal c i rcu i t , where

36

a count ing algor i thm measures and averages there per iods. An

accurate reference clock is der ived f rom an inexpensive external

3.58MHz crystal .

The t ime requi red to detect a val id tone pai r tdP is a funct ion o f

decode algor i thm, tone f requency, and the previous state o f the

decoded logic. Est (ear ly , s teer ing output) ind icates that two

tones o f val id f requency have been detected and in it iates an RC

t iming c i rcui t . I f both tones are present fo r a minimum guard

t ime, determined by an external RC network, the DTMF signal i s

decoded and the resul t ing data latched on the output register. The

delayed steer ing output (stD) is ra ised to indicate that new data is

avai lable. (The output corresponding to each key pressed is

shown in the t ru th tab le)

3 .6.2.1Tone detect ion

After receiv ing a DTMF tone the DTMF decoder (MT8870) p laces

the corresponding b inary number on i ts out put (StD) goes h igh to

state that new data is avai lable. The detect ion o f the delayed

steer ing output is to the durat ion o f the received DTMF receiver

has al ready been explained.

37

Figure.3.9 Pin Diagram of IC MT8870

3 .6.2.3 Funct iona l Descr ip t ion

The MT8870D/MT8870D-1 monol i th ic DTMF receiver o f fers

smal l s ize, low power consumpt ion and h igh per formance. I ts

archi tecture consists o f a band spl i t f i l ter sect ion, which

separates the h igh and low group tones, fo l lowed by a d ig i ta l

count ing sect ion which ver i f ies the f requency and durat ion o f

the received tones before passing the corresponding code to

the output bus.

Fi l ter Sect ion

Separat ion o f the low-group and h igh group tones is achieved by

app ly ing the DTMF signal to the inputs o f two s ix th-order

swi tched capaci tor band pass f i l ters, the bandwidths o f which

38

cor respond to the low and h igh group frequencies. The f i l ter

sect ion also incorporates notches at 350 and 440 Hz for

except ional d ia l tone re ject ion (see Figure 3). Each f i l te r output

i s fo l lowed by a s ingle order swi tched capaci tor f il ter sect ion

which smoothes the s ignals pr ior to l imi t ing. L imi ting is

per formed by h igh-gain comparators which are prov ided wi th

hysteresis to prevent detect ion of unwanted low- level s ignals.

The outputs o f the comparators provide fu l l ra i l log ic swings at

the frequencies of the incoming DTMF signals.

Decoder Sect ion

Fol lowing the f i l ter sect ion is a decoder employing d ig i ta l

count ing techniques to determine the Frequencies o f the incoming

tones and to ver i fy that they correspond to standard DTMF

f requencies. A complex averaging algor i thm protects against tone

s imulat ion by ext raneous signals such as voice whi le provid ing

to lerance to smal l f requency deviat ion and var iat ions. This

averaging algor i thm has been developed to ensure an opt imum

combinat ion o f immuni ty to ta lk-o f f and to lerance to the presence

o f in ter fer ing f requencies ( th i rd tones) and noise. When the

detector recognizes the presence o f two va l id tones ( th is is

re ferred to as the “s ignal condi t ion” in some industry

speci f icat ions) the “Ear ly Steer ing”(ESt ) output wil l go to an

act ive state. Any subsequent loss o f signal condi t ion wi l l cause

ESt to assume an inact ive state. The steer ing c ircui t works in

39

reverse to va l idate the inter d ig i t pause between signals. Thus, as

wel l as reject ing s ignals too shor t to be considered val id , the

receiver wi l l to lerate s ignal in ter rupt ions (dropout) too shor t to

be considered a va l id pause. This faci l i ty , together wi th the

capabi l i ty o f select ing the steer ing t ime constants external ly,

a l lows the designer to ta i lor per formance to meet a wide var iety

o f system requi rements.

3.6.2.4 Guard Time Adjustment

In many s i tuat ions not requ ir ing select ion o f tone durat ion and

inter d ig i ta l pause, the s imple steer ing c i rcui t shown in Figure 4

is app l icable. Component values are chosen according to the

formula:

tREC=tDP+tGTP

t ID=tDA+tGTA

The va lue o f tDP is a device parameter and tREC is the

min imum signal durat ion to be recognized by the receiver .

Di f ferent steer ing arrangements may be used to select

independent ly the guard t imes for tone Present ( tGTP) and tone

absent ( tGTA). This may be necessary to meet system

speci f icat ions which p lace both accept and reject limi ts on both

tone durat ion and interd ig i ta l pause. Guard t ime adjustment a lso

al lows the designer to ta i lor system parameters such as ta lk o f f

and noise immuni ty . Increasing tREC improves ta lk-of f

40

per formance s ince i t reduces the probabi l i ty that tones s imulated

by speech wi l l maintain signal condi t ion long enough to be

registered. Al ternat ively , a relat ively short tREC wi th a long tDO

would be appropr iate for ext remely noisy. Environments such as

fast acquisi t ion t ime and immunity to tone drop-outs are requi red.

3.6.2.6 Features

• Complete DTMF Receiver recommended for most appl icat ions,

leav ing R to be se lected by the designer

• Low power consumption

• In ternal gain set t ing ampl i f ier

• Central o f f ice qual i ty

• Power-down mode

• Inhib i t mode

• Backward compat ib le wi th MT8870C/MT8870C-1

3.6.2.7 Appl icat ions

• Paging systems

• Repeater systems/mobi le rad io

• Credi t card systems

• Remote contro l

• Personal computers

41

• Telephone answering machine

3.3 VOLTAGE CONVERTER (MAX232)

Th e MAX220–MAX249 fami ly o f l ine dr ivers/ receivers is

in tended for a l l EIA/TIA-232E and V.28/V.24 communicat ions

in ter faces, part icu lar ly appl icat ions where ±12V is not avai lable.

These par ts are especial ly usefu l in bat tery-powered systems,

s ince the i r low-power shutdown mode reduces power dissipat ion

to less than 5µW.

Feature

• Operate from Single +5V Power Supply

• Low-Power Receive Mode in Shutdown

• Meet Al l EIA/TIA-232E and V.28 Speci f icat ions

• Mult ip le Dr ivers and Receivers

• 3-State Dr iver and Receiver Outputs

42

3.6.3.1 PIN Diagram

F igure 3.10Pin Diagram of MAX232

Since the RS232 is not compat ible wi th today’s mic roprocessors

and microcontro l lers, we need a l ine dr iver (vol tage converter) to

convert the RS232’s s ignals to TTL vol tage levels that wi l l be

acceptable to the 8051’s TxD and RxD pins. One example o f such

a converter i s MAX232 f rom Maxim Corp. The MAX 232 converts

f rom RS232 vol tage levels to TTL vo l tage levels, and v ice versa.

One advantage of the MAX232 chip is that i t uses a+5V power

source which is the same as the source vol tage for the 8051.

43

3 .3.2 Funct iona l Diagram of MAX232

F igure 3.11 Funct ional Diagram of MAX232

The MAX232 has two sets o f l ine dr ivers for t ransfer r ing and

receiv ing data, as shown in Figure 10-7. The l ine dr ivers used for

TxD are cal led T1 and T2 whi le the l ine d r ivers for Rxd are

designated as R1 and R2. In many appl icat ions only one o f each

is used for example, T1 and R1 are used together for TxD and

44

RxD of the 8051 and the second set i s le f t unused. Not ice in

MAX232 that the T1 l ine d r iver has a designat ion o f T1 in and T1

out on p in numbers 11 and 14, respect ive ly . The T1 in p in is the

TTL side and is connected to TxD of the microcontrol le r, whi le

T1 out is the RS232 side that is connected to the RxD pin o f the

RS232 DB connector.

The R1 l ine dr iver has a designat ion o f R1 in and R iout on p in

numbers 13 and 12, respect ively . The R1 in (p in 13) is the RS232

s ide that i s connected to the TxD p in o f the RS232 DB connector,

and R1 out (p in 12) is the TTL s ide that i s connected to the RxD

pin o f the microcontro l ler . See f igure 10-7. Not ice the nul l

modem connect ion where RxD for one is TxD for the other .

MAX232 requi res four capaci tors ranging f rom 1 to 22F. The

most widely used value for these capaci tors is 22nf.

3.3.3 APPLICATIONS

• Portable Computers

• Low-Power Modems

• In ter face Translat ion

• Bat tery-Powered RS-232 Systems

• Mult id rop RS-232 Networks

45

CHAPTER 4

CIRCUIT EXPLANATION

46

4.1 CIRCUIT DIAGRAM

Figure 4.1 Circuit Diagram with landline interface

47

4.2 CIRCUIT OPERATION

• When the telephone is in the idle condition, the voltage will be -48V.

• When the ringing occurs, it will be 125V peak to peak AC signal superimposed on -48V.

• The opto isolator is used to isolate the microcontroller from high voltage AC

signals and it consists of GaAs infrared emitting diode optically coupled to a monolithic silicon phototransistor.

• The microcontroller will detect the ring through the port 1.5 and it will count the number of rings.

• After a fixed number of rings, the microcontroller will send a signal to the relay and then the automatic off-hooking of the telephone takes place. At the same time, microcontroller will transmit ‘Z’ to the computer which is an indication to play the ‘Welcome’ message.

• The relay used is DPDT type and after automatic off-hooking takes place, the relay connects the telephone lines to the decoder IC 8870 and isolation transformer.

• The transformer used is a line transformer used to isolate voice card from high voltages.

• As the telephone lines are connected to the voice card, the caller gets to hear the stored messages and asks the caller to enter the roll number of the student whose result is to be known. After the caller dials the roll number from the touch tone keypad of his telephone, that number will be decoded by the decoder IC 8870 and the decoded information will be sent to the computer via the microcontroller.

48

• Computer on receiving the decoded information will check the database to access the result of the student whose roll number is entered.

• Then the computer will send the desired information to the voice card and the caller will get to hear the result of the student on his telephone through the voice card.

4.2.1 Telephone Ring sensor

This Ci rcui t can be used to connect any te lephone to the

te lephone l ine. When the te lephone handsets are in on-hook

posi t ion, the current through the optocoupler LEDs is inadequate

to act ivate thei r inbui l t t ransistors. However the r ing s ignal

passes to te lephone in paral le l s ince the te lephone l ine is

connected to the te lephone instruments through combinat ion o f

inbui l t LEDs o f optocouplers in paral le l wi th reverse d iodes

whi le the ‘ - ‘marked te lephone l ine is connected to the relay.

In i t ia l ly when the handsets o f a l l the te lephones are on the

cradles, the optocoupler wi l l not conduct adequately and as such

the emit ters o f inbui l t t ransistors o f optocouplers are at low

level . The t ransistor output avai lable at the emit ters are inver ted

to logic 1 state and appl ied to the Microcontro l ler.

In th is c i rcu i t optocoupler i s used to sense the r ing signal . A r ing

vol tage f rom exchange is around 70 to 90vol t (25 HZ AC) come

49

via te lephone l ines. The te lephone l ine is connected to the r ing

sensor (optocoupler IC MCT2E) wi l l detect th is s ignal and the

capaci tor C2 (1µ f/25v) bypasses the 13.5mA to60maA, AC

r inging current so that the optocoupler get turned ON ( the d iode

ant iparal le l wi th the LED) an optocoupler provide condi t ion

dur ing the negat ive hal f cycle o f the r inging current . As the

resul t , t ransistor T1 gets forward b iased and i t conducts, pul l ing

i t ’s co l lector towards ground. This wi l l turn ON the re lay by

provid ing the magnet iz ing current . This wi l l Ceases the DC

vol tage across the phone l ine. The audio signal is extended to the

ON/OFF hook detector (Optocoupler IC). I f the te lephone hand set

i s ON hook cond i t ion means the te lephone L ine consist o f 48v, to

get a c losed loop connect ion wi th the exchange for

communicat ion. Here an optocoupler i s used for ON/OFF hook

detect ion, i t gets th is 48v as input and the photodiode acqui re a

conduct ion vol tage around 12v by the use o f resistor R1. The

conduct ion o f photodiode emi ts l ight towards photo t ransistor and

thereby i t gets the GND, which connect a 10k resistor (R2) across

the Telephone Line. So that the exchange detect a signal f rom the

subscr ibers, that the subscr iber was ready for communicat ion. I f

the te lephone l ine is used for message Tx and Rx means, the hand

set is f i rst p icked up to conform that the incoming signal is Voice

or Message .Af ter that the subscr iber can p lace the hand set wi th

the base set . Once the hand set i s p icked up means the µ c wi l l

sent a acknowledgement signal to the µ c at the designat ion s ide

.so that the hook detector wi l l p rov ide vol tage drop in the Land

50

l ine vol tage, there by a c losed loop c ircui t i s formed between

Subscr ibers and Telephone exchange.

I f i t i s a Voice s ignal means the ON/OFF hook detector funct ion

is same and the Hand set i s used for Voice communicat ion. Once

the hand set i s p laced wi th the base set a fter the voice or message

communicat ion means the Relay connected wi th Ring sensor get

de-energized and Telephone l ine is d isconnected by the µ c.

Optocoupler ( IC MCT2E)

The MCT2E opto isolators consist o f a gal l ium arsenide in f rared

emit t ing d iode dr iv ing a si l icon photot ransistor in a 6-p in dual

in- l ine package.

F igure.4.2.1 Photo transistor Optocouple

Feature

51

• UL recognized (Fi le # E90700)

• VDE recognized (Fi le # 94766)

• MCT2 and MCT2E are also avai lable in whi te package by

speci fy ing -M suff ix , eg. MCT2-M

Schematic d iagram

F igure 4.3 Schemat ic d iagram of optocoupler

Appl icat ion

• Power supp ly regulators

• Dig i ta l log ic inputs

• Microprocessor inputs

52

4.2.2 ON/OFF HOOK SIMULATOR

During r ing s ignal 70 to 90V rms a t 20 -25HZ AC wi ll come

through the te lephone l ine from the Exchange bat tery. The

outgoing signal ing re fers s ignal reaching the exchange from the

subscr ibers te lephone, indicat ing ON-hook, OFF- hook, hang up,

d ia l ing etc. Once the hand set is p icked up means it is in o f f hook

condi t ion and now the vol tage reduces to 47v to 48v and ( i t i s

g iven to input on ON/OFF hook detector optocoupler IC)Cradle

swi tch c loses to form a c losed loop ci rcui t wi th the exchange

bat tery and the te lephone c ircui t . This c i rcu i t i s re ferred as the

local loop c ircui t . Exchange bat tery vol tages are typ ical ly 48

vol ts. The loop cur rent is used by the exchange to establ ish

ON/OFF hook status o f the te lephone. I f the loop cur rent i s

13.5mA to 60mA the exchange detects i t as OFF hook condi t ion

and i f the loop cur rent is less than 7.5mA the exchange interprets

i t as ON hook condi t ion.

The operated l ine vol tage is about 50v DC and the incoming

voice vol tage to the te lephone instrument var ies f rom 0.5v to 1

vol t and the maximum out going voice vol tage is abut 2v rms.The

r ing signal is 70- 90v rms at 20 -25HZ. In pulse d ial ing

te lephones register s ignal ing is known as DC loop signal ing. In

th is case the d ialed number is conveyed to the exchange by

“make” and “break” o f loop c ircui t .

53

When a r ing signal i s present , the microcontro l ler wi l l

swi tch on the RELAY to achieve OFF hook condi t ion.

4.2.2.1 RELAY

The re lay is one o f the most widely used components in industr ia l

e lectronics. In combinat ion wi th t ransistors, SCRs, e lect ron tubes,

and other c i rcu i t e lement , th is electromagnet ic device per forms

count less tasks. This re lays are used as protect ive dev ice for

swi tching, for ind icat ing and for t ransmission.

Transmission relays are used in conjunct ion wi th t ransformers,

inductors, capaci tors in power system and in te lephone and in

other communicat ion systems. Relays are e lect ro magnet ical ly

operated remotely contro l led swi tches wi th one or more sets o f

contacts. When energ ized, the relay operates to open o r c lose i ts

contacts or to open some contacts and close others. Contacts which

are open when the re lay is not energized are cal led normal ly open

(NO) or simply open contacts. Contacts, which are closed when the

relay is not energ ized, are cal led normal ly c losed contacts.

F igure.4.4 Relay

54

Relay contact are held in thei r normal posi t ion e i ther by spr ing or

by some gravi ty act ivated mechanism. An ad justment or adjustments

are usual ly prov ided to set rest rain ing force to cause the re lay to

operate wi th in predetermined ci rcui t condi t ions.

Relays are e lect ro magnet ic components which has an operat ing coi l

and contact . The coi l shal l be energized wi th AC or DC supply.

Accordingly re lays are avai lable wi th AC\DC operat ing coi ls o f

var ious magni tudes say from 6V DC to 220 V DC or for AC vol tages

ranging from 20V AC to 440 AC.

The operat ing pr incip le o f re lays is as fo l lows when the coi l is

energized, an i ron core at tached to th is assembly gets magnet ized.

This then at t racts an armature which has elect r ica l connected to i t .

The elect r ica l terminals should be fabr icated in such away that there

shal l be one common terminal ; one normal ly c losed (NC) contact

and one normal ly open (NO) contacts. When the relay is not

energized the connect ion is c losed between common and NO

contacts th is state is reversed when the relay is energized th is re lay

c i rcu i t shal l be used to swi tch on other power c i rcu i ts, using low

contro l vo l tage. The power c i rcu it and contro l c i rcu i t are pract ical ly

i so lated.

55

4.2.3 Serial Ports in Computer

Al l IBM PC and compat ib le computers are typ ical ly equ ipped

wi th two ser ia l por ts and one paral le l port . Al though these two

types o f por ts are used for communicat ing wi th external devices,

they work in d i f fe rent ways.

A para l le l por t sends and receives data eight b i ts at a t ime over 8

separate wi res. This al lows data to be t ransfer red very quick ly;

however, the cable requi red is more bulky because of the number

o f ind iv idual wi res i t must conta in. Paral le l por ts are typ ical ly

used to connect a PC to a pr inter and are rarely used for much

else. A ser ia l port sends and receives data one b i t a t a t ime over

one wire. Whi le i t takes e ight t imes as long to t ransfer each byte

o f data th is way, only a few wires are requi red. In fact , two-way

( fu l l duplex) communicat ions is possib le wi th only three separate

wi res - one to send, one to receive, and a common signal ground

wire.

RS-232C

RS-232 stands for Recommend Standard number 232 and C is the

latest rev is ion o f the standard. The ser ia l por ts on most

computers use a subset o f the RS-232C standard. The fu l l RS-

232C standard speci f ies a 25-pin "D" connector of which 22 p ins

are used. Most o f these p ins are not needed for normal PC

56

communicat ions, and indeed, most new PCs are equipped wi th

male D type connectors having only 9 p ins.

Pin deta i ls of PC ser ia l port

RICTSRTSDSR

GNDDTRTDRDCD

RS232Connector

67895

4321

9 P in Connector on a DTE device (PC

connect ion)

P in

Number Direct ion of s ignal :

1 Carr ier Detect (CD) ( from DCE) Incoming s ignal f rom

a modem

2 Received Data (RD) Incoming Data from a DCE

3 Transmit ted Data (TD) Outgoing Data to a DCE

4 Data Terminal Ready (DTR) Outgoing handshaking

s ignal

5 Signal Ground Common re ference vol tage

57

6 Data Set Ready (DSR) Incoming handshaking signal

7 Request To Send (RTS) Outgoing f low contro l s ignal

8 Clear To Send (CTS) Incoming f low contro l s ignal

9 Ring Indicator (RI) ( f rom DCE) Incoming s ignal f rom

a modem

Table 4.1 Pins o f RS232

4.3 POWER SUPPLY

58

F igure 4.5 Power Supply Uni t

The power supply sect ion is the important one. I t should del iver

constant output regulated power supply for successfu l work ing o f

the pro ject . A 0-12V/500mA t ransformer is used for our purpose;

the pr imary o f th is t ransformer is connected in to main supply

through on/o f f swi tch& fuse for protect ing f rom overload and

short c i rcu i t p rotect ion. The secondary is connected to the d iodes

convert f rom 12V AC to 12V DC vol tage, which is fu rther

regulated to +5v, by using IC 7805.

4.3.1 Regulator IC (LM 7805)

The LM7805 monol i th ic 3- terminal posi t ive vo l tage regulators

employ in ternal cur rent- l imi t ing, thermal shutdown and safe-area

compensat ion, making them essent ia l ly indestruct ib le. I f adequate

heat s ink ing is provided, they can del iver over 1.0A output

cur rent . They are in tended as f ixed vol tage regulators in a wide

range o f appl icat ions inc luding local (on-card) regulat ion for

e l iminat ion o f noise and d ist r ibut ion problems associated wi th

s ingle-point regulat ion. In addi t ion to use as f ixed vol tage

regulators, these devices can be used wi th external components to

obtain ad justable output vol tages and currents.

Considerab le ef for t was expended to make the ent i re ser ies o f

regulators easy to use and minimize the number o f external

components. I t is not necessary to bypass the output, a l though

59

th is does improve t ransient response. Input bypass ing is needed

only i f the regulator i s located far f rom the f i l ter capaci tor o f the

power supply.

F igure.4.6 Pins of LM780

60

CHAPTER 5

SOFTWARE DESCRIPTION

61

5.1 Visual Basic 6.0

Visual Basic (Visual Beginners Al l purpose symbol ic

Inst ruct ion Code) is the most popular programming language for

world ’s most popular operat ing system. Visual Basic is the f i rst

language people consider when they want rapid appl icat ion

development for the window envi ronment . Visual Basic is

evo lved from the or ig ina l BASIC language, which is widely used

language. Ex ist ing ob jects are dragged & dropped in to the p lace

instead o f wr i t ing numerous codes. Whi le wr i t ing the programs,

we are able to see how the programs run dur ing the run t ime. This

is great advantage over other programming language. VB is based

on an event dr iven method model; i t a lso has a set o f debugging

tools. The pr imary reason behind select ing VB was because the

inter face was so l i t t le compared to o ther tools.

Proper t ies

The propert ies descr ibe the appearance o f the GUI component .

When adding a component , the Name property should be set

immediately , according to the three- let ter mnemonic naming

convent ions. The propert ies are d isplayed in the Propert ies

Window in Name/Value pai rs in alphabet ical order.

Event Procedures

62

An event procedure is a p iece o f code that responds to

events that can occur for that object . Most of the events are

generated by the user, enabl ing them to d ic tate the order o f

execut ion.

5.2. Visual Basic (Seria l Communication)

5.2.1 Int roduct ion

This chapter d iscusses how Visual Basic can be used to access

ser ia l communicat ion funct ions. Windows hides much o f the

complexi ty o f ser ia l communicat ions and automat ically puts any

received characters in a receive buf fer and characters sent in to a

t ransmission buf fe r. The receive bu ffer can be read by the

program whenever i t has t ime and the t ransmi t buffer is empt ied

when i t is f ree to send characters.

5.2.2 Communicat ions contro l

Visual Basic a l lows many addi t ional components to be added to

the too lbox. The Microsoft Comm. component is used to add a

ser ia l communicat ion faci l i ty . In order to use the Comms

component the f i les MSCOMM16.OCX ( for a 16-bi t module) or

MSCOMM32.OCX ( for a 32-bi t module) must be present in the

\WINDOWS\SYSTEM directory. The class name is MSComm. The

63

communicat ions contro l prov ides the fo l lowing two ways for

handl ing communicat ions

Event -dr iven

Event-dr iven communicat ions is the best method o f handl ing

ser ia l communicat ion as i t f rees the computer to do other th ings.

The event can be def ined as the recept ion o f a character , a change

in CD (carr ier detect ) or a change in RTS (request to send). The

OnComm event can be used to capture these events. and also to

detect communicat ions errors.

Pol l ing

CommEvent propert ies can be tested to determine i f an event or

an error has occurred. For example, the program can loop wai t ing

for a character to be received. Once i t i s the character i s read

f rom the receive buf fer. This method is normal ly used when the

program has t ime to pol l the communicat ions receiver or that a

known response is imminent .

Visual Basic uses the standard Windows dr ivers for the ser ia l

communicat ion ports (such as ser ia lu i .d l l and ser ial .vxd) . The

communicat ion contro l i s added to the appl icat ion for each port .

The parameters (such as the b i t rate, par i ty , and so on) can be

changed by select ing Contro l Panel ? System ? Device Manager ?

Ports (COM and LPT) ? Port Set t ings. The sett ings o f the

64

communicat ions port ( the IRQ and the port address) can be

changed by se lect ing Contro l Panel? System? Dev ice Manager?

Ports (COM and LPT)? Resources for IRQ and Addresses.

Proper t ies

The Comm component is added to a form whenever ser ia l

communicat ions are requi red. By defaul t , the f i rs t created object

i s named MSComm1 ( the second is named MSComm2, and so on) .

I t can be seen that the main propert ies o f the object are:

CommPort , DTREnable, EOFEnable, Handshaking, InBufferSize,

Index, InputLen, InputMode, Left , Name, Nul lDiscard,

OutBuf ferSize, Par i tyReplace, RThresho ld, RTSEnable, Set t ings,

SThreshold, Tag and Top.

Set t ings

The Set t ings property sets and returns the RS-232 parameters,

such as baud rate, par i ty , the number o f data b i t , and the number

o f stop b i ts. I ts syntax is :

[ form.] MSComm.Set t ings = setS tr[$]

where the st rStr i s a st r ing which contains the RS-232 set t ings.

This str ing takes the form:

"BBBB,P,D,S"

65

where

BBBBdefines the baud rate,

P the par i ty ,

D the number of data b i ts , and

S the number o f stop b i ts.

The fo l lowing l is ts the va l id baud rates (defaul t is 9600Baud):

110, 300, 600, 1200, 2400, 9600, 14400, 19200, 38400, 56000,

128000, 256000.

The val id par i ty va lues are (defaul t is N) : E (Even), M (Mark) , N

(None), O (Odd), S (Space).

The val id data b it values are (defaul t is 8) : 4, 5, 6, 7 or 8.

The val id stop b it values are (defaul t is 1) . 1, 1.5 or 2.

An example o f set t ing a contro l por t to 4800Baud, even par i ty , 7

data b i ts and 1 stop b i t is: Com1.Set t ings = "4800,E,7,1"

CommPort

The CommPort property sets and returns the communicat ion port

number. I ts syntax is:

[ form.] MSComm.CommPort = portNumber[%]

which defines the portNumber from a value between 1 and 99. A

value o f 68 is returnedi f the por t does not ex ist .

66

PortOpen

The PortOpen property sets and returns the state o f the

communicat ions por t . I ts syntax is :

[ form.] MSComm.PortOpen = [{True | False}]

A True set t ing opens the port , whi le a False c loses the port and

clears the receive andtransmi t buf fers ( th is automat ical ly happens

when an appl icat ion is c losed). The fo l lowing example opens

communicat ions port number 1 (COM1:) at 4800 Baud wi th even

par i ty , 7 data b i ts and 1 stop b i t :

Input t ing data

The three main propert ies used to read data from the receive

buf fer are Input , InBuf fer Count and InBuf ferSize.

Input

The Input property returns and removes a str ing o f characters

f rom the receive buf fer . I ts syntax is:

[ form.] MSComm.Input

To determine the number o f characters in the bu ffer the

InBuf ferCount property is tested ( to be covered in the next

67

sect ion) . Set t ing InputLen to 0 causes the Input property to read

the ent i re contents o f the receive buf fer.

InBuf ferSize

The InBuf ferSize property sets and returns the maximum number

o f characters that can be received in the receive buf fer (by

defaul t i t is 1024 bytes). I ts syntax is :

[ form.] MSCommInBuf ferSi ze = [numBytes%]

The s ize o f the buf fer should be set so that i t can store the

maximum number o f characters that wi l l be received before the

app l icat ion program can read them from the buf fer .

The InBuf fe rCount property re turns the number o f characters in

the receive buf fe r. I t can also be used to c lear the buf fer by

set t ing the number o f characters to 0. I ts syntax is :

[ form. ]MSCommInBuf ferCount= [count%]

68

CHAPTER 6

METHODOLOGY

69

6.1 Micro Control ler

Algor i thm

STEP 1: Star t the program

STEP 2: Check whether r ing s ignal is present or not.

STEP 3: I f r ing signal is present , make te lephone OFF HOOK and

send ‘Z’ s ignal to Personal Computer, e lse go to STEP 2.

STEP 4: Get the DTMF signal through the DTMF decoder.

STEP 5: Send the DTMF data to the pc through the ser ia l por t and

go to STEP 4.

70

6.2 VISUAL BASIC

Algor i thm

STEP 1: Star t the program

STEP 2: Check for the data ‘Z’ .

STEP 3: I f data is present, p lay the welcome message, else go

to step 2.

STEP 4: Play the message to enter the ro l l number.

STEP 5: Check whether Rol l number is entered or not.

STEP 6: I f yes, check the database for that ro l l number and te l l

the rank to user.

71

CHAPTER 7

APPLICATIONS

72

7.1 BANKING & FINANCE Technological innovations have brought about not just new types of electronic money, but also new bank-customer relationships. These relationships are fuelling the demand for more and more innovative banking services such as: • Call Center with Customer Relationship Management Software • Credit Card Activation System • Credit Card Authorization • Forex Enquiry by Speech Recognition • Stock Quote By Speech Recognition • Telephone Banking System • Telephone Loan Approval • Trade & Account Inquiry Service • Voice Recording System

8.2 EDUCATION Apart from providing an environment for learning, educational establishments are now improving their quality of service, offering a better level of support to both students and to the public through: • Enquiry Hotline • Library Book Renewal • Student Registration System • Student Result Declaration System 8.3 GOVERNMENT In order to improve the efficiency of information accessibility, many government departments such as the Labour Department, the Education Department, the Immigration Department, the Inland Revenue and the Department of Health, have already implemented IVRS systems to provide hotline services.

73

8.4 TELECOMMUNICATIONS In this highly competitive industry, we can help telecom service providers (wire line or wireless) to develop infrastructure and add value to their services through: • Prepaid Roaming • Postpaid Calling Card, Prepaid Calling Card, and Wireless Prepaid (or Mobile Prepaid) • Mobile Number Portability • Number Change Announcement • Fax Stored-And-Forward Service • Signaling Protocol Converters • Telecom Call Center

74

CHAPTER 8

Conclusion

&

Future Enhancement

75

7.1 CONCLUSION

The system designed will be intelligent for interaction and will suitably provide a good response to the caller who will access it. It will be truly a responsible system for human mankind. We will make it better than the present scenario system. It will be digitally accessed and will have a strong data base and can be operated easily and of low cost. And the future will show that every organization will be using our system.

7.2 FUTURE ENHANCEMENT

In future, the concept of Interactive Voice Response System can be used in various transport departments like Bus transport, Metro rail, Railways and Airports as the transport companies not only need to be fast and responsive, but also need to provide customers with an easily accessible information system providing: • Information Enquiry • Schedule Enquiry • SISR Information Enquiry • Teleticketing System So, in near future, all the information regarding routes, timings etc. will be known through the Interactive Voice Response System.Also, this concept may be implemented in Cinema halls and Multiplexes where the caller will get to know the timings of his favourite movies as well as he can book his tickets through this system.

76

APPENDIX 1

Source Code

77

Microcontroller Code

org 0000h

sjmp power_on

org 0003h

LJMP ISR

org 000bh

LJMP COUNTER

org 0013h

reti

org 001bh

reti

org 0023h

LJMP SERIAL

reti

power_on:

mov ie,#00h

mov ip,#00h

mov p0,#0FFH

MOV P1,#0FFH

MOV P2,#11111011B

MOV P3,#0FFH

78

RAM:

MOV R0,#07FH

CLR:

MOV @R0,#00H

DJNZ R0,CLR

INITIALIZE:

MOV IE,#10010011B

MOV IP,#00010000

MOV TMOD,#26H

MOV TH1,#0FDH ;SET BAUD RATE 9600 B/S

MOV SCON,#50H ;SETS SERIAL MODE 1,8-BIT DATA,1 STOP,1 START BIT

SETB TR1

SETB TCON.0

MAIN:

MOV TH0,#100

MOV TL0,#100

SETB TR0

M: SJMP M

DELAY:

MOV 30H,#3

79

RAJ2:

MOV 31H,#23

RAJ1:

MOV 32H,#234

RAJ:

DJNZ 32H,RAJ

DJNZ 31H,RAJ1

DJNZ 30H,RAJ2

RET

ISR:

MOV A,P1

SUBB A,#192 ;WHEN WE RESET DTMF IC ,THEN ALSO IT COMES TO ISR BCOZ IT GETS

AN INTERRUPT

MOV SBUF,A ;SBUF=0000(P0.3-P0.0)

RETI

COUNTER:

SETB P2.2 ;OFF-HOOKS RELAY

CLR P2.0 ;SWITCH ON THE EXTRA LED CONNECTED IN SINK

MOV SBUF,#'Z'

RETI

80

SERIAL: JB RI,TRANS

CLR TI

RETI

TRANS: CLR P2.2

SETB P2.0

CLR RI

RETI

Visual Basic Code

Option Explicit

' Plays the sound specified by

' lpszPlaySound. This function is

' limited to .wav files.

Private Declare Function sndPlaySound _

Lib "winmm.dll" _

Alias "sndPlaySoundA" ( _

ByVal lpszSoundName As String, _

ByVal uFlags As Long) _

As Long

Private Const SND_NOWAIT As Long = &H2000 ' Don't wait if the driver is busy

81

Private Const SND_SYNC As Long = &H0 ' Play synchronously (default)

Private Const SND_FLAGS As Long = SND_SYNC Or SND_NOWAIT ' Combination of two constants

above

Private Sub Form_Load()

' Fire Rx Event Every single Bytes

MSComm1.RThreshold = 1

' When Inputting Data, Input 1 Byte at a time

MSComm1.InputLen = 1

' 9600 Baud, No Parity, 8 Data Bits, 1 Stop Bit

MSComm1.Settings = "9600,N,8,1"

' Disable DTR

MSComm1.DTREnable = False

' Open COM1

MSComm1.CommPort = 1

MSComm1.PortOpen = True

End Sub

Private Sub MSComm1_OnComm()

82

Dim Data As String, X As Integer, i As Integer

Static z As Integer

Static y As Integer

Adodc1.Recordset.MoveFirst

X = Adodc1.Recordset.Fields("ASCII").Value

' If comEvReceive Event then get data and display

If MSComm1.CommEvent = comEvReceive Then

Data = MSComm1.Input 'get data

If z = 1 Then

GoTo elec

z = 0

ElseIf y = 1 Then

GoTo civ

y = 0

End If

If Data = "Z" Then

' Call sndPlaySound to play our file

Call sndPlaySound("D:\ivrs" & "\bugsbunny1.wav", SND_FLAGS)

83

ElseIf Data = "1" Then

z = 1

Call sndPlaySound("D:\ivrs" & "\bugsbunny1.wav", SND_FLAGS)

Print "1 detected"

ElseIf Data = "2" Then

Adodc1.RecordSource = "CIVIL"

Adodc1.Refresh

Print "2 detected"

y = 1

End If

GoTo out

elec:

Print "entered elec"

Do

' For i = 1 To 10

If X = Asc(Data) Then

Select Case X

Case 49

Call sndPlaySound("D:\ivrs" & "\daffyduck1.wav", SND_FLAGS)

Print X

Case 50

Call sndPlaySound("D:\ivrs" & "\familyguy1.wav", SND_FLAGS)

84

Print X

Case 51


Print X

Case 52

Call sndPlaySound("D:\ivrs" & "\austinpowers.wav", SND_FLAGS)

Print X

Case 53

Call sndPlaySound("D:\ivrs" & "\goodmorningvietnam.wav", SND_FLAGS)

Print X

Case 54

Call sndPlaySound("D:\ivrs" & "\jamesbond.wav", SND_FLAGS)

Print X

Case 55

Call sndPlaySound("D:\ivrs" & "\robocop(2).wav", SND_FLAGS)

Print X

Case 56

Call sndPlaySound("D:\ivrs" & "\robocop.wav", SND_FLAGS)

Print X

Case 57

Call sndPlaySound("D:\ivrs" & "\starwars.wav", SND_FLAGS)

Print X

End Select

Exit Do

85

Else

Adodc1.Recordset.MoveNext


'Print x

End If

'Next i

Loop Until Adodc1.Recordset.EOF = True

z = 0


GoTo out

civ:

Print "entered civil"

Do

' For i = 1 To 10

If X = Asc(Data) Then

Select Case X

Case 49


Print X

Case 50

Call sndPlaySound("D:\ivrs" & "\familyguy1.wav", SND_FLAGS)

86

Print X

Case 51


Print X

Case 52

Call sndPlaySound("D:\ivrs" & "\austinpowers.wav", SND_FLAGS)

Print X

Case 53

Call sndPlaySound("D:\ivrs" & "\goodmorningvietnam.wav", SND_FLAGS)

Print X

Case 54

Call sndPlaySound("D:\ivrs" & "\jamesbond.wav", SND_FLAGS)

Print X

Case 55

Call sndPlaySound("D:\ivrs" & "\robocop(2).wav", SND_FLAGS)

Print X

Case 56

Call sndPlaySound("D:\ivrs" & "\robocop.wav", SND_FLAGS)

Print X

Case 57

Call sndPlaySound("D:\ivrs" & "\starwars.wav", SND_FLAGS)

Print X

End Select

Exit Do

87

Else



'Print x

End If

'Next i

Loop Until Adodc1.Recordset.EOF = True

y = 0


GoTo out

End If

out: Print "out"

End Sub

Private Sub Form_Unload(Cancel As Integer)

MSComm1.PortOpen = False 'Close the COMM port

End Sub

Private Sub cmdfirst_Click()


88

End Sub

Private Sub cmdlast_Click()

Adodc1.Recordset.MoveLast

End Sub

Private Sub cmdnext_Click()


End Sub

Private Sub cmdprevious_Click()

Adodc1.Recordset.MovePrevious

End Sub

'ElseIf Data = "1" Then

'Call sndPlaySound("F:" & "\911.wav", SND_FLAGS)

'ElseIf Data = "2" Then

'Call sndPlaySound("F:" & "\ghostbustersray.wav", SND_FLAGS)

89

REFERENCES

Websites: 1. http://en.wikipedia.org/wiki/Interactive_voice_response 2. http://web.cmc.net.in/products/ivrs/ivrs.asp 3. http://www.blissit.org/ivrs.htm 4. http://www.kleward.com/ivr_solutions.htm 5.http://en.wikipedia.org/wiki/Special:Search?search=information+on+IVR+system 6. http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VRG- 4C0RRMJ-4&_user=7427940&_coverDate=08%2F05%2F2004&_alid=810799566&_rdoc= 6&_fmt=high&_orig=search&_cdi=6234&_docanchor=&view=c&_ct=7&_acct= C000050221&_version=1&_urlVersion=0&_userid=7427940&md5=58db2884bc bc7ed43d9119ed01eefe1a Books: 1. Thiagarajan Vishwanathan/Telecommunication Switching System & Networks/India PRI Pvt.ltd/Second Edition 2. Kenneth J.Ayala/The 8051 Microcontroller Architecture ,Programming and Applications/India/PRI Pvt.ltd/Second Edition 3. Douglas V.Hall/Microcontroller and Interfacing/New York/TMH Publishing Company Pvt Ltd/Second Edition

Documents

Project Report Final PrintNEW