LESSON 8 OFFICE AUTOMATION STRUCTURE 8.0
OBJECTIVES
8.1
INTRODUCTION
8.2
TELEPHONE 8.2.1 8.2.2 8.2.3 8.2.4 8.2.5 8.2.6 8.2.7 8.2.8
8.3
TELEPHONE AND ITS PRINCIPLE OF OPERATION BRIEF HISTORY INSTALLATION OF THE FIRST TELEPHONE FIRST EVER USE OF THE TELEPHONE NUMBERS BASIC WORKING OF A TELEPHONE APPLICATION AND USAGE TECHNOLOGICAL ADVANCEMENTS ADVANTAGES AND LIMITATIONS OF A TELEPHONE
EPABX AND INTERCOM 8.3.1 MAIN FEATURES OF EPABX 8.3.2 APPLICATIONS AND USAGE AREA 8.3.3 DISADVANTAGES AND LIMITATIONS OF EPABX
8.4
FASCIMILE OR FAX 8.4.1 8.4.2 8.4.3 8.4.4 8.4.5
8.5
HISTORY TYPES OF FACSIMILE DEVICES PRINCIPLE OF OPERATION APPLICATION / USAGE OF A FAX MACHINE ADVANTAGES AND LIMITATIONS
ASSIGNMENTS 8.5.1 CLASS ASSIGNMENTS 8.5.2 HOME ASSIGNMENTS
8.6
SUMMING UP
8.7
POSSIBLE ANSWERS TO SELF-CHECK QUESTIONS
8.8
TERMINAL QUESTIONS
8.9
REFERENCES AND SUGGESTED FURTHER READING
8.10
GLOSSARY
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8. OFFICE AUTOMATION Communication is an integral part of daily life. In modern offices, it is very important to transmit information in form of verbal messages, documents and copies of documents in the shortest possible time with little or no distortion of information. Primarily the following four equipments play an important role in office automation: •
Computers
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Telephones
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EPABX and Intercoms and
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Facsimile or Fax machines
Out of these four equipment computers have already been described in Lesson 7 and their uses in office management will be dealt with in Lesson 9, which will include some interesting uses as the Internet, email etc. In this lesson, the three remaining equipments, their main features, operation, functions and applications will be described.
8.0
Objectives After going through this lesson you will be able to understand:
8.1
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Main features of telephones, EPABX & Fax machine.
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Operation and function of the telephone, EPABX & Fax machine.
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Applications of the telephone, EPABX & Fax machine.
Introduction
Some equipment in offices help us reach the goal of effective communication. To communicate verbally, we have the Telephone and the EPABX (Electronic Private Automatic Branch Exchange). The telephone helps us reach the outside world through the EPABX .The telephone in the form of an intercom also helps us communicate verbally within the organization. To send documents to distant locations instantaneously, a machine called the Facsimile or Fax as it is popularly known, is very popular. The effective usage of these equipments is very important for you to communicate effectively as well as improve your own productivity in the organization.
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8.2
Telephone
8.2.1 Telephone and its principle of operation A telephone is a telecommunications device that is used to transmit and receive sound (most commonly voice and speech) across distances. Literally translated, the word ‘telephone’ stands for: tele = far away and phone = voice. It is a system of reproducing sounds at a distance. It is an apparatus for transmitting sound (especially speech) to a distance by wire, cord, or radio usually by converting acoustic vibrations into electrical signals for transmission. It is a system of communication by a network of telephones. Most telephones operate through transmission of electric signals over a complex telephone network, which allows almost any phone user to communicate with other telephone subscribers. A caller is able to establish contact with the other person simply by dialing his / her telephone number. 8.2.2 Brief history Alexander Graham Bell is considered to the inventor of telephone. Although a German experimenter, Philipp Reis did come out with a primitive model of telephone, for various reasons like patenting a much improvised version than Reis’ in the year 1876, the invention of telephone stands on the name of Bell. The picture below is the of the telephone invented by Bell. At that time he called it ‘Electrical speech Machine’ which we now call as telephone. Seen differently the second picture on the left is that of the first ever telephone. A.G. Bell invented it in the year 1876.
A.G. Bell and his telephone
8.2.3 Installation of the first telephone The first telephone ever, was installed by the then American president Rutherford B. Hayes administration in the White House in 1878. The first outgoing call went to Alexander Graham Bell himself, only thirteen miles distant. It is interesting to note that Hayes first words instructed Bell to speak more slowly.
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8.2.4 First ever use of the telephone numbers Telephone numbers were first used in the latter half of year 1879 and in the early half of 1880, at Lowell, Massachusetts. It seems until then the telephone subscribers were addressed by a mode other than the telephone numbers. At that time there was an outbreak of an epidemic of measles at Lowell. Then, Dr. Moses Greeley Parker feared that the four telephone operators of Lowell too might be affected by the disease. If so happened, he thought, then the entire telephone service would come to a halt. Then he thought there was a need to evolve a system for a unique access to each telephone subscriber. This need led to the idea of using unique telephone numbers for identifying the telephone subscribers. By instituting the system of using telephone numbers, it would be easier to train new telephone operators in case an existing operator left the job due to any reasons whatsoever. Parker was convinced of the telephone’s potential, and hence felt the need to sustain the telephone service by taking due care of it. Until year 1950, the telephone numbers were typically a combination of alphabets and numbers. 8.2.5 Basic working of a telephone •
Essentials of a Telephone System
The three basic essentials of a telephone system are: i) A telephone set to convert sound into electrical impulses and back again. ii) A transmission system to carry these signals over a distance (with acceptable limits of distortion and attenuation ), and iii) A Switching system to connect any two telephone sets. Such connections are now usually made automatically as the caller, by dialing the required number, sends out a series of pulses, which activate the switching system, and are monitored electronically. •
Operation
When the subscriber lifts the receiver, a dial tone is transmitted to the subscriber, informing him that he may now dial. The dialled digits route the call through the several switching stages before the called line is connected. If the line is engaged, a ‘busy’ tone is returned to the calling subscriber. If the line is free, the bell is rung by ringing current applied to the required subscriber’s line. A ‘ring’ tone is transmitted to the calling subscriber to inform him that the required number is being rung. When the call is answered, the ring tone stops. The call is 4
automatically metered against the caller, and the exchange equipment completes a speaking circuit. The connection is held under the control of the calling party. When the call is complete, the calling party may disconnect the call. 8.2.6 Application and usage Telephone is used to connect to people located far and wide. It is widely used in homes, offices, corporate establishments and other organizational entities. In the wake of globalization, it has become even more important to connect to people at physically distant locations. By using a telephone, you can talk to people, give some urgent piece of information, discuss an issue or seek some information. Enables information transfer, removes ambiguity and gives you the opportunity to send and receive clear messages. 8.2.7 Technological advancements Until recently, a ‘telephone’ generally referred only to landlines. A landline is a fixed line connection wherein the handset is connected to the telephone equipment with a wire. Advancements in telephones on the aspect of its mobility led to the increasing use of cordless phones and mobile phones. Since cordless phones and mobile phones are widely used across homes and offices, it will be useful for you to have the basic information about it. •
Cordless phone Wireless Handset
Base Station
A cordless telephone is a telephone with a wireless handset, which communicates with a base station connected to a fixed telephone landline. It is a wireless phone because its handset is connected to its base station with radio waves. This phone is portable as one can simply pick up the handset and move around an area. It can be operated within a radius of 100 metres of its base station (Exact radius of mobility depends on the particular Model.). Its base station is charged with electricity. It requires regular power supply for its operation.
8.2.8 Advantages and limitations of a telephone •
Advantages o It enables you to instantly connect to people at far off locations. o It saves cost and time, as you need not physically travel to talk to people. o It is the ideal mode of communication for sending urgent messages. o It helps you to speed up your business transactions. o It also helps you to develop your social life as you are able to maintain your contacts through regular conversations.
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•
Limitations
A telephone is a boon to the society that has become a part of people’s life. Its limitations, if any, are far outweighed by its utility.
Self-check Questions 1.
Who invented the telephone and in which year?
2.
What are the three essentials of a telephone system?
3.
Fill in the blanks: i) Most telephones operate through the ______________ of electrical signals over a complex telephone network. ii) A landline is a _______ ______ connection where the handset is connected to a telephone through a wire. iii) A cordless telephone is a telephone with a _____________ __________ which communicates with a base station connected to a fixed telephone landline.
4.
What is the basic application and usage of a telephone?
5.
What is the basic advantage of a cordless phone in comparison to a normal telephone?
8.3
EPABX and Intercom
As you have learnt in the previous topic, the telephone is a very important part of day to day communications. This chapter helps you understand how the telephone connects to other telephones (intercoms) within the same company as well as how it connects to the rest of the people outside the company premises 8.3.1 Main features of EPABX •
Intercom Calls – Making an Internal Call from one Extension to another within the same office. All one needs to do is to pick up his phone and press the numeric extension number of the extension he wish to call within the office
•
External Calls – Also Known as Outgoing calls, is when a user (extension) calls up a number outside the office i.e., using a Public Exchange Line (DOT/MTNL) to a person in any part of the world. Normally this is accessed by dialing ‘0’ or ‘9’ depending on the make of the EPABX and then he gets a dial tone of the main Trunk line and then dials the telephone number of the called party and make the conversation
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Conference Facility – This is a feature when more than two internal or external users can talk to each other together at the same time. This can be of two types, Internal or external Conference, Internal Conference is wherein the users are all within the same organization or in the same 6
Private exchange(EPABX) and the External Conference is one where one or more users are outside the EPABX •
Call transfer – When one extension transfers the call which he is currently talking to another extension within the office then the same is known as Call Transfer facility. This facility can again be Internal Call Transfer or External Call transfer
•
Automatic Call Back – This is a feature wherein one can programme a called party to automatically call back. This is activated by a code wherein the caller calls up another extension which is either not being answered or is coming busy, then by the press of a specific numeric code, can activate the Auto Call Back feature.
•
Call Forwarding – When a user is moving from his desk to another one and wants his calls to come there, then he can programme the same by entering a specific numeric code from his or the extension where he wants the call to come and then all the calls which would normally ring on his original desk get diverted to the other place where he has programmed it to be forwarded. These calls can also be forwarded to an external number (through the Public Exchange), In this case the same feature is known as External Call forwarding.
These are just a few out of tens of features which an EPABX can do. Also as explained above, an EPABX can perform lot of these functions through various numeric codes unlike the Key telephone system which can do the same functions on a press of a key. 8.3.2 Applications and usage area As mentioned above, an EPABX is primarily an equipment by virtue of which one can communicate within the office or to the outside world. EPABX are currently used in practically all the offices having 10 or more or even lesser number of persons. Besides it also find it usage in residential segment as well for e.g. in multi storied buildings, housing societies, colonies etc. 8.3.3 Disadvantages and limitations of EPABX It is actually difficult to imagine life without communication today and thus EPABX has become actually a necessity in any Office environment due to the following •
EPABX is enabling the Communications both Inter and Intra office much more simpler, faster and easier
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It is increasing the overall efficiency in the office.
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It saves loads of time required to communicate both within the organization and outside the office.
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It also results into lot of cost reduction as people do not need to travel to places for communicating or delivering messages etc.
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With the current technology, one can in fact also use certain advanced features and even enable features like Video Conferencing etc through these equipment and thus reduce lots of cost of operations as well. 7
There are however few limitations also in an EPABX as well •
All EPABX requires Electricity to run the equipment though one can use an UPS for backup
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Since it is an Advanced Electronic Equipment therefore it needs careful handling of the equipment
•
Also it is operated through various numeric codes or function keys and thus one need to avoid playing around with the various instrument unnecessarily as they can change the programming in the Equipment and causing problems
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It is an equipment which has to be installed and fixed at one place and cannot be transported without the help of a technical person
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Cost of maintenance also is on a little higher side, though there are very few running costs.
Self-check Questions 6.
8.4
What is the full form of EPABX?
FASCIMILE or FAX
In the device known as Fascimile, one telephone connects to other telephones between two offices to transmit documents over the telephone lines through a machine called the ‘FASCIMILE’ commonly known as the ‘FAX’. Through this device, we can transmit still pictures, or printed matter, over an electrical circuit to another destination. It is also called facsimile or picture telegraphy. It is a method of sending messages by a telecommunications link. It transmits text and graphic data such as photographs, maps and diagrams. Virtually anything on paper can be transmitted by facsimile equipment. Most fax transmissions are via the telephone network.. A fax machine is especially useful when documents are to be sent urgently. The basic technique is not new – for years it has been possible to wire photographs – but recent advances in technology have made it cheap and reliable, and it is now in widespread use. Seen below are a few examples of fax machines.
Two examples of fax machines
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8.4.1 History The fax machine evolved from the telegraph technology. Alexander Bain invented a fax machine capable of receiving signals from a telegraph wire and translating them into images on paper. First introduced in 1842, facsimile did not have a real impact until computers and telecommunication networks were developed. 8.4.2 Types of facsimile devices Currently, there are three basic types of facsimile devices available. The first group that is analog units is declining in popularity. Low speed Units: This group includes devices that scan, transmit, and print out at the receiving end in 4 to 6 minutes. These were the first machines introduced and they use analog technology. These are rarely used nowadays. Medium Speed Units: Devices in this group have transmission speeds that range from 1 to 3 minutes and use either analog or digital technology. Many units in this category are compatible with units in the slower category and hence may have lower transmission speeds. High speed Units: Devices in this category use digital technology exclusively and feature transmission speeds of less than a minute. These type of machines are most popularly used in organizations. 8.4.3 Principle of operation Facsimile Transmission requires two facsimile machines – a sender and a receiver- connected by phone. Sending Unit: The document is scanned optically (by the means of a light spot), line by line, or by breaking it into a pattern of dots, which are transmitted as electrical pulses. The variations in tone of the picture are interpreted into variations in the amplitude of A.C. (Alternating Current) passed to line to a receiver. Receiving Unit: Here a light from a constant source is arranged to fall on a piece of photographic material and scan this at exactly the same rate as the sender light spot. The variation of incoming current from the line operates a light valve, which controls the intensity of the light falling on the photographic material to reproduce the original picture. The receiving device reconstructs the image from this digital information and outputs it on photosensitive paper or in some machines, xerographically. •
Steps in sending a FAX message 1. The image of the document to be faxed is scanned. 2. It is transmitted as a series of impulses. 3. The image is reconstructed by the facsimile receiver at the receiving end.
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4. After the successful transmission of fax message, a transaction report is generated by the sending unit. The transaction report consists of details of fax message transmitted.
Sample Fax transaction report
The above transaction report shows the following details: Communication mode: The fax was manually transmitted, hence the phrase ‘manual transmit’. Communication speed: The speed of transmission is mentioned. Connection telephone: The telephone number of the Receiving unit is mentioned. Pages: Number of pages faxed. Start time: The time at which fax transmission was done. Duration: The transmission time spent in sending the fax. Result: PASS result indicates successful transmission of fax message. What is a Facsimile receiver: A device that reproduces an image transmitted over a conventional telephone line by accepting and converting AM voice – frequency or digital signals to D.C. (Direct Current) signals. The dc signals activate a stylus on the receiver, or modulate light when making a photographic recording. Facsimile scanner: A synchronously rotating drum or flat plate on which a document is spirally scanned by a light bean to produce a varying dc signal which is then converted to an AM voice – frequency signal for transmission of the facsimile.
Buttons of a Fax machine
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This model of fax machine combines Fax, Scanner and a Copier. Its functional areas are: •
ON:
Power Button
•
ENTER: It works like the ‘select’ key of the various options displayed. The left and the right arrows above this button display various menu and submenus of options. These options may relate to light / dark print or the resolution etc. The desired options may be selected by pressing the enter button.
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FAX: To select the fax option. (Scan and copy options are meant for scanning and photocopying)
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CANCEL: To cancel the command given to the machine.
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BLACK, COLOUR: For the colour of printing (some models have a printer facility too).
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NUMBER PAD: Number pad on the left is used to key in the numbers.
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PAPER TRAY: Just below the main machine set-up is the in-paper tray, where the papers are inserted. The fax messages are received on these sheets. These sheets are ejected from the paper tray placed just above the number pad.
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REDIAL: To dial the last dialled number again
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SPEED DIAL: To speed up the dialing
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START: To send / receive a fax
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SETUP: Default options are restored
Fax messages may be received on two kinds of paper: •
Thermal: Glossy paper, print is removable. After a few days of storing this paper, the message fades off.
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Ordinary Paper: Ordinary paper may alternatively be used to receive fax messages. Its print is long lasting.
8.4.4 Application / usage of a Fax machine It is now finding increasing application, particularly for press work. Organizations such as banks, insurance companies, brokerage houses, and other financial institutions frequently have a need to transmit applications, transfers, letters of credit, and other forms requiring a legally valid signature. Because many businesses utilize widely dispersed branch offices, the transmission of such documents by fax can permit a greater degree of consultation between geographically distant people. It shall be particularly useful in circumstances where agreement must be reached on a complex document by an imminent deadline. 8.4.5 Advantages and limitations
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Fax machines are essential tools of any office that needs to transmit graphic images. Some of its benefits are: •
Precise reproduction of an original document: It provides the recipient with a document that is an exact copy of the sender’s original document. Other type of transmission devices cannot duplicate this capability of exact duplication. An inbuilt advantage is that the message transmitted is available for records. For ex: A telephone conversation can transmit the same information but at the end of the conversation, there is no hard copy of what transpired. On the contrary, fax equipment transmits a message by generating a duplicate copy of the original message. Hence, it is only natural that a hard copy is available for record purposes.
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High Transmission speed: The transmission of document from the sending machine to the facsimile receiver is almost instantaneous. Just as the sending and receiving of voice is immediate in a telephone, so is the case with the transmission of a document through a fax equipment. It provides an alternative to regular postal service; because the transmission time is much faster than either postal service or specialized couriers.
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Accuracy of data: Also, by not having to rekey data, the facsimile eliminates one of the principal sources of errors.
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Facsimile equipment can operate unattended at night, thus reducing costs because it operates at low phone-line rates during that time. If instructed, it can also produce a self-monitoring report of what it sent, to where, and when, which can be checked the next morning.
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A fax machine can be cost-justified on its own unique capabilities. For example: Fax transmission can eliminate postage costs and delivery delays.
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Facsimile transmission of correspondence and other routine business communication saves labor as well as processing and distribution time.
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There is no risk of losing the documents in transit.
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Despite its advantages, certain small establishments may find its cost to be relatively higher.
Self-check Questions 7.
State whether the following statements are true or false: i) Most fax networks operate on telephone lines? ii) The facsimile was invented by Alexander Bain. iii) Fax machines cannot use plain paper.
8.
True / False True / False True / False
Fill in the blanks: i) The term fax refers to a device that __________ still pictures, or printed matter, over circuit to another destination. ii) There is no risk of ____________ the documents in transit using a fax machine.
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8.5
Assignments
8.5.1 Class assignments i)
Prepare a short communication for sending through FAX.
8.5.2 Home assignments i)
Observe the arrangement of a telephone directory and list out STD codes of important countries and cities.
ii)
Observe how a fax is sent and try to send a sample fax through a fax machine. Use the short communication prepared in the class assignment.
8.6
Summing Up
The equipment that have contributed to office automation viz., telephones, EPABX and FAX, have been described in terms of their architecture, mode of operation, recent developments and applications. It has been shown how these have contributed to efficiency in office management.
8.7
Possible Answers to Self-check Questions
1.
Alexander Graham Bell invented the telephone in the year 1876.
2.
The three essentials of a telephone system are i) Telephone set, ii) transmission system, iii) switching system
3.
Fill in the blanks: i) Most telephones operate through the transmission of electrical signals over a complex telephone network. ii) A landline is a fixed line connection where the handset is connected to a telephone through a wire. iii) A cordless telephone is a telephone with a wireless handset which communicates with a base station connected to a fixed telephone landline.
4.
Basic application of the telephone is connecting people and its basic usage is in homes, offices, corporate establishments & other organizations.
5.
What is the basic advantage of a cordless phone in comparison to a normal telephone is its mobility.
6.
The full form of EPABX is Electronic Private Automatic Branch Exchange.
7.
State whether the following statements are true or false: i) Most fax networks operate on telephone lines?
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ii) The facsimile was invented by Alexander Bain. iii) Fax machines cannot use plain paper. 8.
True True
Fill in the blanks: i) The term fax refers to a device that transmits still pictures, or printed matter, over circuit to another destination. ii) There is no risk of losing the documents in transit using a fax machine.
8.8
Terminal Questions
1.
What is the primary use of a telephone?
2.
What are the advantages of a cordless phone?
3.
What does EPABX stand for? Explain its functions.
4.
Name three different types of Fax machines?
5.
What types of paper are used in a Fax machine?
6.
Can one print copy from a fax machine?
8.9
References and Suggested Further Reading
1. http://en.wikipedia.org 2. http://www.answers.com
8.10 Glossary 1.
Landline Telephone:
A landline is a fixed line telephone wherein the handset is connected to the telephone equipment with a wire or a connecting cord.
2.
Cordless Telephone:
A telephone with a wireless handset that communicates with a base station connected to a fixed telephone landline. Its handset is connected to its base station via radio waves.
3.
Mobile Phone:
A term covering cellular phones, satellite phones, and any phone giving wide-ranging mobility. It operates over a wide area via a cellular network of base stations (cell sites), which are further linked to the conventional telephone network.
4.
Cell/cellular phone:
Term used to refer to most mobile phones. It technically applies specifically to mobile phones that use a cellular network.
5.
Calling Party / Caller:
A person who initiates a telephone call.
6.
Called party:
A person to whom the telephone call is made. 14
7.
Subscriber:
A person who has been allotted a particular telephone connection is the subscriber to that telephone number. He / she pays a regular sum for the hire of a telephone.
8.
Telephone number:
It uniquely identifies a particular telephone connection. Its number code represents its geographical area and the network area it belongs to.
9.
Dial tone:
A continuous buzzing sound that can be heard on picking up the telephone receiver. Most commonly, it indicates that the telephone is in working order.
10. Automated Redial:
A facility to dial the last dialed number once again, simply at the press of a button.
11. Call Forwarding:
The call is forwarded to the called party at some other number in case the called party is not available at the dialed number.
12. Call Waiting:
An indication that a next call is incoming and needs to be attended by the called party.
13. Caller ID:
Identification of the caller displayed on the telephone equipment of the called party.
14. Conference call:
A caller is able to connect telephonically with more than one person simultaneously enabling him to hold a discussion with all of them.
15. Hands Free or Speaker Phone: This is a feature on some phones only. When you press the speakerphone button, it transfers the voice to a speaker. Thus, you can hear the voice of the incoming party without lifting the handset. A microphone also lets you speak without lifting the hand set 16. STD / ISD services:
STD services permit a subscriber to make outstation calls to another state / city. STD refers to nationally bound calls, while ISD facility refers to international bound calls.
17. Telephone Directory:
It contains the names, addresses, full particulars and other contact details of all subscribers. It is organized in alphabetical order. Business directories are separately published wherein details of corporate organizations are published.
18. Phone Index:
A personal telephone diary consisting of names, telephone numbers, addresses and other details of relevant individuals, organized or indexed alphabetically. It is a useful record for future reference.
19. Phone etiquette:
Certain accepted mannerisms, behavioral patterns to be observed while using the telephone. Ex: Beginning a call with a personal greeting, avoiding background noise, constantly nodding to show that you are listening etc. 15
There are several terminologies being used while referring to an EPABX however, the basic name of EPABX also denotes the following: 20. Electronic:
Since the switching was Electronic therefore the term ELECTRONIC
21. Private:
Since it was owned privately and not being provided by the government such as MTNL/BSNL (which are known as PUBLIC Exchanges)
22. Automatic:
Since the switching was automatically done and not mechanically, therefore the word Automatic
23. Branch:
An EPABX is nothing but a miniature versions of the Main Public exchange and works on the End Points of the Public exchange and then branches out into various extension in the office or in other words actually functions as a branch of the Public exchange and thus the word Branch and finally
24. Exchange:
Exchanging the Information (Communication) or in technical terms the Main Box, which housed the switching equipment.
Few other terminologies that one should know of before using an EPABX are as below: 25. Trunk Lines:
Also known as the CO (Central Office) or P&T (Post and telegraph) or technically speaking known as the Trunk lines are actually the outside telephone number (Lines) coming from the Public Services Provider (DOT/MTNL or BSNL) which are terminated in our EPABX and are our connection to the outside world.
26. Extensions:
These are the internal telephones, which are available at the user end and are the user interface to dial out internally or externally through the numeric keypad on them
27. Intercom system
Intercom systems as the name suggest was primarily for internal communications. These were of two kinds the initial one was the Electromechanical and the later one being the Electronic version of the same.
28. Cabinet or the Main Box
It is the Cabinet has a Mother board, PSU and several slots on which the CPU and all the other cards of the EPABX are fixed.
29. Mother Board
Mother board is the Main board which has the slots on which all the cards are plugged 16
including the CPU, Trunk and extension cards 30. CPU
It is the module wherein all the Intelligence of the system is and where the Main Microprocessor is embedded. This Microprocessor is the one that controls the speed of switching and processing the data, currently the Chip being used is of 32Kbps. Besides, the CPU also has the Programme controller which is different in different types of exchanges on which the entire data and the software programme of the Exchange is stored. This can be in the form of an EPROM or an Hard Disk or the latest Multimedia Card.
31. PSU
This is the Power Supply Unit which provides the Power to the CPU and to the other modules of the Exchange. This on one side is connected to the AC Mains and on the other side to the Exchange. Normally this is also resides in the Main Box as such.
32. Trunk Cards
These are the modules wherein the Trunk Lines (P&T) Lines are terminated from the MDF and thus is the connectivity to the outside world. Normally these cards come in the denomination of 4, 8 or 16 Trunk Lines
33. Extension Cards
These are the cards wherein the Internal Intercom Extensions are connected to through the MDF. These also come in the denomination of 4, 8, 16, 24 or 32 Lines depending upon the make
34. MDF
Main Distribution Frame is a Box which is where all the field cables from Intercom stations (Extensions) and the trunks are terminated. From here there is a Multi core cable which connects the MDF to the Mother board which resides in the Main Box of the EPABX
35. Operator Console
This is the equipment from which the status of all Incoming calls or the extension is displayed on a screen and there is an operator who uses this to receive and transfer the calls from outside to the internal users.
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