SUBMITTED BY:MANISH KUMAR PANDEY
ROLL NO.- 1003331054
ECE 7TH SEM
INTRODUCTION OF BHEL HARIDWAR
CARDS USED IN EXCHANGE
FREQUENCY USED IN TELEPHONY
VOLTAGE USED IN TELEOHONES LINES
TELEPHONE LINE IN BHEL
MAKING A TELEPHONE CALL
TYPES OF CONNECTIONS IN TELECOMMUNICATION
INTRODUCTION TO BHEL
BHEL is one of the Maharatna company and is only PSU among 12 Indian
companies to figure in Fobes Fabulous of 50 list.
BHEL Haridwar was established in 1965.
The areas of BHEL operations broadly cover conversion, transmission, utilization
and conservation of energy in core sectors of the economy like Power, Industry
and Transportation etc., and fulfill vital infrastructure needs of the country.
BHEL have 14 manufacturing divisions, 8 service divisions, 15 regional offices, 4
power sectors and more than 150 project sites in all over India.
Product of BHEL are boiler , Gas generator, hydro generator , Steam turbines, gas
turbines , Hydro turbines, AC motors ,Transformers, Wind mill, Valves, etc.
The financial turnover during the year 2007-08 was 21,401 crore rupees and
current in 2012-13 turnover is 1,20,000 crores rupees.
TELECOMMUNICATION IS A FAR COMMUNICATION PROCESS IN WHICH
MODULATION OF MESSAGE IS REQUIRED.
TELECOMMUNICATION IS BASICALY COMMUNICATION DONE THROUGH
TWO TYPES OF TELEPHONY COMMINICATION IS USED
1. MANUAL TELECPHONY :-OPERATOR IS REQUIREDTO ESTABLISH CONNECTION
MANUALLY B/W THE DIFFERENT CALLING & CALLED SUBSCRIBERS.
2. AUTOMATIC TELEPHONY :- OPERATOR ARE NOT REQUIRED TO ESTABLISH
CONNECTION MANUALLY B/W THE DIFFERENT CALLING & CALLED
IN THIS CALLING SUBS. ESTABLISH REQUIRED CONNECTION BY
OPETRATING THE DIFFERENT SWITHS AT THE CENTRAL PLACE KNOWN AS
TONE USED IN TELEPHONY
DIAL TONE – WHEN HANDSET IS PICKED UP FROM THE CRADLE THIS
TONE HEARED IF A FREE LINE IS AVAILABLE.THIS TONE IS A
CONTINUOS BURBLE SOUND OF 400Hz MODULATED BY 25 Hz.
BUSY TONE - CALLED SUBSCRIBER ENGAGED WITH OTHER CALL. THIS
TONE IS A CONTINUOS OF 400Hz, GENERALLY ON FOR 0.75 sec& OF
RINGING TONE - THIS TONE IS A CONTINUOS BURBLE SOUND OF
400Hz MODULATED BY 25 Hz.
NUMBER UNOBTAINED TONE- DIALED NUMBER CONNECTION NOT
PRESENT IN EXCHANGE
CARDS USED IN EXCHANGE
Z-24 :- ANALOG CARD
UA-32 :- DIGITAL CARD
NDDI :- JUNCTION CARD
ATR-2 :- DIT CARD
CPU-3 :- CONTROL PROCESSING UNIT
INTOF :- INTERFACE CARD
MMSFD :- FLOPPY DRIVE USED BY OWNER
SUVG :- VOICE CARD (LIKE- NUMBER IS BUSY TRY AFTER SOME
9. IDTL-8 :- LOOP DIALING
10.PCM-2 :- DIGITAL TRUNK CARD USED THROUGH OPTICAL FIBER
11.GPA-1 :- CONFERENCE CARD
FREQUENCY USED IN TELEPHONY
IN TELEPHONE DIALING TWO TYPES OF FREQUENCIES ARE USED
1. HIGH BAND FREQUENCY:• RANGE OF FREUENCY IS 1216 Hz TO 1245 Hz
• NUMBER FROM 6 TO 9 AND 0 FALL UNDER THIS BAND
2. LOW BAND FREQUENCY
• RANGE OF FREQUENCY IS 701Hz TO 936 Hz
• NUMBER FROM 1 TO 5 FALL UNDER THIS BAND
VOLTAGE USED IN TELEPHONE LINE
40 TO 60 VOLT DC ALWAYS REMAIN IN NORMAL
9 TO 12 VOLT WHEN HANDSET IS PICKED UP
75 TO 110 VOLT DC AT THE INSTANT OF RINGING
TELEPHONE LINES IN BHEL
THREE TYPES OF TELEPHONE LINE
1. MAX LINE - FOR INTERNAL COMMUNICATION LINK IN
2. PABX - USED FOR BOTH INTERNAL & EXTERNAL
COMMUNICATION LINK IN BHEL
3. DOT LINE - THESE LINE ARE DIRECT TELEPHONE LINE
HOW TELEPHONE CALL IS MADE
1. PICK UP HANDSET &DIAL TONE IS HEARED
2. DIAL A NO.
3. CHECKING OF CALLED SUBSCRIBER LINE WHETHER IT
IS FREE OR NOT
4. IF LINE IS FREE THEN RINGING PULSE IS SEND TO THE
5. WHEN CALLING PARTY PICKS UP THE HANDSET THE
BILLING METER BECOMES ACTIVE
TYPES OF CONNECTION
TWO TYPES OF CONNECTION MADE IN TELECOMMUNICATION
1. With wire or cables connection:- These are also two types
a). Under ground cables :- These types of cables run under the earth and
used to connect the exchange to the subscriber's
Distribution Box .
b). Over head cables:- These types of cables are used to connect the
equipment inside the exchange and to connect the peripheral devices to
the subscriber's Distribution Box.
2. Wireless Microwave Links through satellite :- wireless microwave
communication is use for long distance communication or where cable
communication is not possible like in sea.
OPTICAL FIBER SYSTEM
For long distance data transmission optical fiber cable is used.
Long distance data transmission in electrical cables suffers from ground loop
problems. The merits of the optical fiber stem from the fact that the basic
material used in their construction is nonmetallic and electrically non
Fiber cables are about the thickness of a human hair and thin dimension
results in a low weight for given length when compared to electrical cables.
Losses through optical fiber are also low . For single mode fiber losses is
about 0.4 DB per km and for multi mode fiber 3 DB per km for wavelength
850 nm. So optical fiber is widely used in telecommunication.
Telecommunication makes life easy. It connect people in few
seconds and information is sent in few minutes. It enhances
collaboration and communication among individuals both inside and
outside an organization and there are many example use of
telecommunication in everyday life and is a necessary part of life
TELECOMMUNICATION is plays a vital role. In India ,there has been
unprecedented growth in last ten year and still growing. Hence
telecommunication is playing a big role in development of India.