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					DATA COMMUNICATION AND NETWORK




      Prepared by:

                          Nazama Liaqat
                     Nicegirl_laj@hotmail.com




   Lahore College For Women University, Lahore
PAKISTAN TELECOMMUNICATION COMPANY LIMITED


Founded          1947

Headquarters     ISLAMABAD, PAKISTAN

INDUSTRY         TELECOMMUNICATION

Website          www.ptcl.com.pk




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Table Of Contents
1.1. Goals and objectives…………………….…………………………….…………..1
1.2. Area of Study………………………………………….…………….…………….1
1.3. Scope:……………………………………………………………………………..1
1.4. Method of Data Collection………………………………………………………..1
1.5. PTCL:……………………………………………..................................................2
1.6. COMPANY PROFILE:………………………………………………………………..2
1.7. INTRODUCTION……………………………………………………………………..2
1.8. HISTORICAL BACKGROUND:………………………………………………………..3
1.9. VISION:…………………………………………….................................................5
1.10. Mission…………………………………………………………………………...5
1.11. CORE VALUES:………………………………………..…………………………..6
1.12. WHOLESALE SERVICES:…………………………………………………………...6
1.13. FEATURES:………………………………………………………………………...7
1.14. DIGITAL SUBSCRIBER LINE………………………………………………………..8
1.15. HISTORY AND SCIENCE:………………………………………………………...…8
1.16. HOW DSL WORKS:………………………………………………………………..8
1.17. SPEED:…………………………………………………………………………….9
1.18. MODEM:…………………………………………………………………………..9
1.19. DSL MODEM……………………………………………………………………...9
1.20. NAKED DSL:……………………………………………………………………..10
1.21. FILTER:…………………………………………………………………………...10
1.22. SPLITTER………………………………………………………………………….11
1.23. CABLE:……………………………………………………………………………11
1.24. HERE ARE SOME ADVANTAGES OF DSL:……...…………………………………..12
1.25. TELEPHONE LINES:………………………………………………………………..13
1.26. How PTCL Actually Works……………………………………………………...13
1.27. Main Distribution Frame (MDF):………………………………………………..13
1.28.INTEGRATED SERVICES DIGITAL NETWORK:………………………………………14
1.29. NEXT GENERATION NETWORK…………………...................................................15
1.30. TELEPHONE EXCHANGE…………………………………………………………..16
1.31. Pre-Digital Automatic Exchanges………………………………………………..17
1.32. CABINET:………………………………………………………………………….18
1.33. OPTICAL NETWORK UNIT (ONU)…………………………………………………18
1.34. Limitations and Problems faced………………………..………………………...19




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     This document is the analysis report for the survey of PTCL Office.

1.1 GOALS AND OBJECTIVES
     The purpose of this survey is to get the knowledge of the trends about: -
        1. What is DSL ?
        2. How PTCL & DSL works.
        3. What are the standards followed by PTCL for the transmission of data, voices
        And etc.
        4. What are advantages and disadvantages of using PTCL DSL?


1.2 AREA OF STUDY
      We have focused our study on the nine knowledge areas of PMI. These nine knowledge
areas are:
              1. Techniques used by DSL
              2. Organization of DSL
              3. Suggestion for Final project

 There were very few direct questions, which would relate to these areas, whereas the questions
 related to these areas were scattered throughout the document in an indirect way.

.1. SCOPE:
 We have visited PTCL office and we collect views of different people through Questionnaires.

1.3 METHOD OF DATA COLLECTION: -
        1. Methodology:
              Questionnaires are the best suitable method of collecting this kind of data but
             only if they are developed carefully and with a vision of goals and objectives in
             mind. We have tried our level best to develop a good questionnaire for the survey.
             We have visited ten software houses for this purpose and collect information
             through the Questionnaire.

        2. Target Population
              Correctly determining the target population is critical. If you do not interview the
              right kinds of people, you will not successfully meet your goals. The target
              population for this Survey was Project Managers, Database Administrators and
              Software Engineers of Software houses. Luckily, all the questionnaires were
              being filled by these persons, which are a factor, which strengthens the
              correctness of information provided.




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1.5 PTCL:
          Pakistan Telecommunication Company Limited (PTCL) is proud to be Pakistan‟s most
      reliable and largest converged services carrier providing all telecommunications services
      from basic voice telephony to data, internet, video-conferencing and carrier services to
      consumers and businesses all over the country.
      Whether it is an office in the largest city of Pakistan or a home in a small village, they are
      present in every corner of Pakistan to serve their customers.

1.6 COMPANY PROFILE:
          PTCL is the largest telecommunications provider in Pakistan. PTCL also continues to be
      the largest CDMA operator in the country with 0.8 million V-fone customers.
      The company maintains a leading position in Pakistan as an infrastructure provider to other
      telecom operators and corporate customers of the country. It has the potential to be an
      instrumental agent in Pakistan‟s economic growth. PTCL has laid an Optical Fibre Access
      Network in the major metropolitan centres of Pakistan and local loop services have started to
      be modernized and upgraded from copper to an optical network.
      On the Long Distance and International infrastructure side, the capacity of two SEA-ME-WE
      submarine cables is being expanded to meet the increasing demand of International traffic.

1.7      INTRODUCTION:
          From the humble beginnings of Posts & Telegraph Department in 1947 and establishment
      of Pakistan Telephone & Telegraph Department in 1962, to this very day, it is a story of
      commitment and vision. Pakistan Telecommunication Corporation (PTC) set sails for its
      voyage of glory in December 1990, taking over operations and functions from Pakistan
      Telephone and Telegraph Department under Pakistan Telecommunication Corporation Act
      1991. This coincided with the Government's competitive policy, encouraging private sector
      participation and resulting in award of licenses for cellular, card-operated payphones, paging
      and, lately, data communication services.
      Pursuing a progressive policy, the Government in 1991, announced its plans to privatize
      PTC, and in 1994 issued six million vouchers exchangeable into 600 million shares of the
      would-be PTCL in two separate placements. Each had a par value of Rs. 10 per share. These
      vouchers        were       converted       into      PTCL         shares      in    mid-1996
      In 1995, Pakistan Telecommunication (Reorganization) Ordinance formed the basis for
      PTCL monopoly over basic telephony in the country. It also paved the way for the
      establishment of an independent regulatory regime. The provisions of the Ordinance were
      lent permanence in October 1996 through Pakistan Telecommunication (Reorganization)
      Act. The same year, Pakistan Telecommunication Company Limited was formed and listed
      on all stock exchanges of Pakistan. Since then, PTCL has been working vigorously to meet
      the dual challenge of telecom development and socio-economic uplift of the country. This is
      characterized by a clearer appreciation of ongoing telecom scenario wherein convergence of
      technologies continuously changes the shape of the sector. A measure of this understanding
      is progressive measures such as establishment of the company's mobile and Internet
      subsidiaries in 1998.
      As telecommunication monopolies head towards an imminent end, services and
      infrastructure providers are set to face even bigger challenges. Pakistan also entered post-


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      monopoly era with deregulation of the sector in January 2003. On the Government level, a
      comprehensive liberalization policy for telecom sector is in the offing.
      Last Year, in middle of 2005 Government of Pakistan had decided to sell at least 26 percent
      of this company to some private agency. There were three participants in the bet for
      privatization of PTCL. Itesalat, a Dubai based company was able to get the shares with a
      large margin in the bet. They were supposed to pay first installment within two months but
      there were some news printed in European Media about financial devastation of PTCL. They
      exposed the ways how Government of Pakistan had depicted some attractive but fake annual
      reports of the company.
      No doubt the company is a back bone in the communication sector of Pakistan but they are
      providing very substandard services to their customers. Being a Government entity they have
      no interest in the problems of a customer. Itesalat has not yet taken over and the dialog at
      Government        level     of     Pakistan       and     UAE       are     in     progress.
      Last year when Government was going to privatize the company there was country wide
      protest and strike by PTCL workers. They even disrupted Phone lines of some big
      Government institutions like Punjab University Lahore and many lines of public sector were
      also blocked. Military had to take over the management of all the Exchanges in the country.
      They arrested many workers and put them behind bars. They contention between
      Government and employees ended with a 30% increase in the salaries of workers.

1.8      HISTORICAL BACKGROUND:
            1947 Posts & Telegraph Dept established
            1962 Pakistan Telegraph & Telephone Deptt.
            1990-91 Pakistan Telecom Corporation
            1995 About 5 % of PTC assets transferred to PTA, FAB & NTC.
            1996 PTCL Formed listed on all Stock Exchanges of Pakistan.
            1998 Mobile (Ufone) & Internet (PakNet) subsidiaries established.
            2000 Telecom Policy Finalized
            2003 Telecom Deregulation Policy Announced
            2006 Etisalat Takes Over PTCL.

 1.9 VISION:
          To be the leading Information and Communication Technology Service Provider in the
      region by achieving customer satisfaction and maximizing shareholders' value'.The future is
      unfolding around them. In times to come, they will be the link that allows global
      communication. They are striving towards mobilizing the world for the future. By becoming
      partners in innovation, they are ready to shape a future that offers telecom services that bring
      them closer.




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1.10 MISSION:
      To achieve their vision by having An organizational environment that fosters
  professionalism, motivation and quality. An environment that is cost effective and quality
  conscious Services that are based on the most optimum technology "Quality" and "Time"
  conscious customer service Sustained growth in earnings and profitability.

1.11 CORE VALUES:
        Professional Integrity
        Customer Satisfaction
        Teamwork
        Company Loyalty

1.12 WHOLESALE SERVICES:
      PTCL customers can now provide services to their clients without undertaking large
  scale investment in infrastructure or developing expertise in running their own networks.




  Experience the Internet at its fastest with high-speed access from Broadband Pakistan,
  simultaneously, enjoy Voice service over the same telephone line without any extra cabling
  connections! Broadband Pakistan offers DSL service with unmatched reliability, affordability
  and connectivity.
  PTCL is now the leader in consumer broadband in Pakistan, leading the country into 21st
  century.
  PTCL offers Free Broadband for the month of December 2008 to all new customers in
  celebration of its coverage in over 119 Cities along with PTCL Smart TV to be Free till
  June 2009 in Karachi, Lahore and Islamabad.
  PTCL management pleased to announce the following tariff for broadband internet facilities
  for its valued customers, with effect from March 1st 2008. The existing package of 256Kbps
  will not be offered to new customers. Existing 256Kbps packages customers will be
  upgraded to 512Kbps package; 512Kbps to 1Mbps and customers of 1Mbps will be upgraded
  to 2Mbps.
  Experience the Internet at its fastest with high-speed access from Broadband Pakistan,
  simultaneously, enjoy Voice service over the same telephone line without any extra cabling
  connections! Broadband Pakistan offers DSL service with unmatched reliability, affordability
  and connectivity. "Broadband Pakistan is now available in over 119 cities including Lahore,


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   Karachi, Islamabad, Rawalpindi, Quetta, Faisalabad, Multan, Hyderabad, Peshawar, Gujrat,
   Gujranwala and Bhawalpur.
   PTCL has become the first company in Pakistan to provide Broadband services in over 100
   cities across the country, whereas before PTCL‟s entry into the Broadband market in 2007,
   Broadband was primarily only available in the 3 major cities of the country. Since the
   Broadband launch in May 2007, PTCL has made the broadband technology affordable by
   lowering the barriers to entry and also by geographically bringing the service within the
   reach of a common user across Pakistan.

1.13 FEATURES:
         Cost effective Always On Internet access
         High speed data download
         Unlimited download
         Free Modem
         Free Installation
         Convenient ordering on phone and web
         No upfront charges

1.14 DIGITAL SUBSCRIBER LINE:
       DSL or xDSL, is a family of technologies that provides digital data transmission over the
   wires of a local telephone network. DSL originally stood for digital subscriber loop,
   although in recent years, the term digital subscriber line has been widely adopted as a more
   marketing-friendly term for ADSL, which is the most popular version of consumer-ready
   DSL. DSL can be used at the same time and on the same telephone line with regular
   telephone, as it uses high frequency, while regular telephone uses low frequency.
   Typically, the download speed of consumer DSL services ranges from 256 kilobits per
   second (kbit/s) to 24,000 kbit/s, depending on DSL technology, line conditions and service
   level implemented. Typically, upload speed is lower than download speed for Asymmetric
   Digital Subscriber Line (ADSL) and equal to download speed for the rarer Symmetric Digital
   Subscriber Line (SDSL).

1.15 HISTORY AND SCIENCE:
       Digital subscriber line technology was originally implemented as part of the ISDN
   specification, which is later reused as IDSL. Higher speed DSL connections like HDSL and
   SDSL have been developed to extend the range of DS1 services on copper lines. Consumer
   oriented ADSL is designed to operate also on a BRI ISDN line, which itself is another (not
   IP) form of digital signal transmission, as well as on an analog phone line.




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1.16 HOW DSL WORKS:
    When you connect to the Internet, you might connect through a regular modem, through a
local-area network connection in your office, through a cable modem or through a digital
subscriber line (DSL) connection. DSL is a very high-speed connection that uses the same wires
as a regular telephone line.




                    A DSL modem

Introduced in late 90s, DSL (digital subscriber line) service entered the country with a bang, but
later failed to thrive as higher cost and lower than standard quality hampered the anticipated
growth of the technology.
The DSL broadband is a modern technology that converts existing twisted pair telephone lines into
access path for high-speed communication of various sorts. By using the technology regular
telephone line can be converted into a high-speed broadband digital link.
DSL is faster than both ISDN (integrated services digital network) and leased line, yet it is more
cost-effective. DSL Internet connection is „always on‟, and the users have unlimited access to the
Internet.

1.17 SPEED:
       What makes DSL technology appealing, first of all, is its speed. In its very fastest
incarnations, DSL offers more than 100 times the network performance of a traditional analog
modem. While the precise speed of a connection depends on the variety of xDSL deployed, even a
basic ADSL setup should outperform those modems by a factor of 20 or more.
Because DSL uses the same telephone line wiring as traditional modems, it may not be
immediately obvious how it achieves such high speed, in a nutshell, DSL works on the unused
(high) frequencies of the line. DSL modems contain an internal signal splitter that carries voice
signal on the usual low frequencies (from 0 up to 4 KHz) and the data signal above that. This
splitter, consequently, allows simultaneous access to the line by the telephone and the computer.
Customers who might ordinarily have required a second phone line won‟t need it for DSL services.




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1.18 ACCESS:
      Ideally, DSL service remains “on” all the time. With an always-on connection customers no
longer need to physically dial up to the internet service provider (ISP) to “log in the internet”.
People should be aware that long lived connections like DSL can have security issues. Many DSL
customers have installed personal firewall products on their home networks to guard against
external attacks.

1.19 MODEM:
      Modem is an abbreviation for Modulator Demodulator. A modem converts data from digital
computer signals to analog signals that can be sent over a phone line (modulation). The analog
signals are then converted back into digital data by the receiving modem (demodulation). A
modem is given digital information in the form of ones and zeros by the computer. The modem
converts it to analog signals and sends over the phone line. Another modem then receives these
signals, converts them back into digital data and sends the data to the receiving computer.

1.20 DSL MODEM:
             ADSL (Asymmetric Digital Subscriber Line) modem or DSL modem is a device used
to connect a single computer or router to DSL phone line, in order to use ADSL service.




                                            A DSL Modem

      A DSL modem, also referred to as an asymmetric DSL (ADSL) modem, provides service
that is similar, with the exception of speed, to that provided by a dial-up modem. However, there
are some major differences in the setup and technological make up of DSL modems. For example,
dial-up modems are frequently, though not always, installed inside computer terminals. By
contrast, a DSL modem is typically external and connects to a computer via a USB or Ethernet
port.
      There are DSL modems that use a USB or Ethernet port, as well as those designed for use
with both. Though a DSL modem may be capable of working with a universal serial bus (USB)
port, most experts recommend the use of an Ethernet port. It is said that the connection is
considerably better when an Ethernet port is used.
      An Ethernet DSL modem can be employed whether the user has a single computer or a
network of PCs. A router can be used to allow more than one computer to enjoy the same Internet



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connection. The router used must be capable of Network Address Translation (NAT). By contrast,
USB modems are recommended for use with single computers only. Usually, a modem connected
via a USB port cannot support a router.

1.21 NAKED DSL:
      Naked Digital Subscriber Line or naked DSL is broadband Internet service without telephone
service, targeting people who have foregone landlines for mobile phones. Also called dry loop,
dryloop, or unbundled DSL, naked DSL makes affordable, high-speed Internet available to all
telco customers. Naked DSL costs a little more than its bundled cousin, but can still be cheaper
than cable Internet alternatives.

1.22 FILTER:
       A DSL filter is an analog low-pass filter installed between analog devices (such as telephones
or analog modems) and a POTS (Plain old telephone service) telephone line, in order to prevent
interference between such devices and a DSL service operating on the same line. Without DSL
filters, signals or echoes from analog devices at the top of their frequency range can result in
reduced performance and connection problems with DSL service, while those from the DSL
service at the bottom of its range can result in line noise and other issues for analog devices.
       Typical installation for an existing home involves installing DSL filters on every telephone,
fax machine, voice band modem, and other voice band device in the home, leaving the DSL
modem as the only unfiltered device. For wall mounted phones, the filter is in the form of a plate
which hangs on the standard wall mount, and upon which the phone hangs in turn.




                          Modern ADSL filter/splitter (left) and filter (right)




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1.23 SPLITTER:
      A DSL splitter, like a DSL filter, is a device used to prevent interference problems. It filters
the low frequencies of the telephone line from the high-frequency ADSL line. However, the
installation of a DSL splitter requires the help of a technician to split the main telephone cable into
2 lines unlike a DSL filter which is easier to install.
      A DSL splitter is installed into one of the lines running to every jack in the house. After
installing the splitter, a new phone point used solely for the ADSL modem will be wired into the
central splitter.
       New technologies now give users the option to have a splitter less DSL. In a splitter less
access, the splitting of the line is done directly from the phone company offices. Splitter less DSL
has recently become the standard for DSL users. However, DSL Internet access still requires a
small filter device to be installed to every analog device that shares the line such as a telephone,
fax machine, voice band, and modem.

1.24 CABLE:
      Setting up a network is fairly easy these days. Each of your computers needs a network card
(NIC), you need a centralized hub or switch, and with the proper tweaking of your computer‟s
network settings, you‟re off to the races.
      The cabling we use is category 5 (CAT 5) with a RJ45 jacks that look like phone jacks but
have 8 wires instead of 2 or 4 wires. The reason of this type of cabling is because almost every
type of network card out there has the jack for this cable. Also this cable allows you to reach faster
speeds than normal coax cable. Also with CAT 5 cabling, you can have each computer connect to
a central hub so that if one of the computers goes down, the other computer can stay online.




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1.25 HERE ARE SOME ADVANTAGES OF DSL:
       You can leave your Internet connection open and still use the phone line for voice calls.
       The speed is much higher than a regular modem
       DSL doesn't necessarily require new wiring; it can use the phone line you already have.
       The company that offers DSL will usually provide the modem as part of the installation.
              But there are disadvantages:
       A DSL connection works better when you are closer to the provider's central office. The
              farther away you get from the central office, the weaker the signal becomes.
       The connection is faster for receiving data than it is for sending data over the Internet.
       The service is not available everywhere.
      In this article, we explain how a DSL connection manages to squeeze more information
        through a standard phone line -- and lets you make regular telephone calls even when
        you're online.

1.26 TELEPHONE LINES:
      If you have read How Telephones Work, then you know that a standard telephone installation
in the United States consists of a pair of copper wires that the phone company installs in your
home. The copper wires have lots of room for carrying more than your phone conversations -- they
are capable of handling a much greater bandwidth, or range of frequencies, than that demanded
for voice. DSL exploits this "extra capacity" to carry information on the wire without disturbing
the line's ability to carry conversations. The entire plan is based on matching particular frequencies
to specific tasks.

1.27 HOW PTCL ACTUALLY WORKS
In civilian telecommunications, the copper access network (also known as the local loop) typically
consists of the following elements:
           In-house wiring that connects customer premises equipment to the demarcation point.
           One or more twisted pairs connect the demarcation point to a street side cabinet or
               Serving area interface.
           The street side cabinet contains a distribution frame.
           The street side cabinet is connected to the main distribution frame, located at the
               central office, by one or more cables which together contain hundreds of copper
               twisted pairs or by optical fiber.
           Jumper cables are installed on both the MDF and the street side distribution frame.
           Active equipment (such as a POTS or DSL line circuit) can then be connected to the
               line in order to provide service, but this is not considered part of outside plant.

1.28 MAIN DISTRIBUTION FRAME (MDF):
      In Telephony, a Main Distribution Frame (MDF or Main Frame) is a signal distribution
frame for connecting equipment (inside plant) to cables and subscriber carrier equipment (outside
plant). The MDF is a termination point within the local Telephone exchange where exchange
equipment and terminations of local loops are connected by jumper wires at the MDF. All cable


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copper pairs supplying services through user telephone lines are terminated at the MDF and
distributed through the MDF to equipment within the local Exchange e.g. repeaters and DSLAM.
Cables to intermediate distribution frames terminate at the MDF. Trunk cables may terminate on
the same MDF or on a separate Trunk Main Distribution Frame (TMDF).
       Like other distribution frames the MDF provides flexibility in assigning facilities, at lower
cost and higher capacity than a patch panel.
       The most common kind of large MDF is a long steel rack accessible from both sides. On one
side, termination blocks are arranged horizontally at the front of rack shelves. Jumpers lie on the
shelves and go through a steel hoop to run vertically to other termination blocks that are arranged
vertically. There is a hoop or ring at the intersection of each level and each vertical. Installing a
jumper requires two workers, one on each side. The shelves are shallow enough to allow the rings
to be within arm's reach, but the workers prefer to hang the jumper on a hook on a pole so their
partner can pull it through the ring. A fanning strip at the back of the termination block prevents
the wires from covering each others' terminals. With disciplined administration the MDF can hold
over a hundred thousand jumpers, changing dozens of them every day, for decades without
tangling.
       For the first half of the 20th Century, all MDF jumpers were soldered. This was reliable but
slow and expensive. In the 1960s wire wrap was introduced, and in the 1970s punch blocks.
       Each jumper is a twisted pair. Middle 20th century jumper wires in the USA were 24 AWG
single strand copper, with a soft polyethylene inner jacket and a cotton wrapper, impregnated to
make it slightly brittle and easy to remove neatly. Late 20th century ones had a single, thicker
coating of polyethylene, cross-linked to provide the correct degree of brittleness.
       Some urban MDFs are two stories high so they don't have to be more than a city block long.
A few are three stories. By British custom the cables to the outside world are terminated on the
horizontal side, and the indoors equipment on the vertical side. American usage is vice versa.
       Smaller MDFs, and some modern large ones, are single sided so one worker can install,
remove or change a jumper. COSMOS and other computerized Operations Support Systems help
by assigning terminals close to one another, so most jumpers need not be long and shelves on
either type of MDF do not become congested. This database keeps track of all terminals and
jumpers. In the early and middle 20th century these records were kept as pencil entries in ledger
books. The later database method saves much labor by permitting old jumpers to be reused for new
lines.
       The adoption of distributed switching in the late 20th century diminished the need for large,
active, central MDFs. The MDF usually holds central office protective devices including heat coils
and functions as a test point between a line and the office. Sometimes the MDF is combined with
other kinds of distribution frame in a CDF. The MDF in a private branch exchange performs
functions similar to those performed by the MDF in a central office. In order to automate the
manual jumpering the Automated Main Distribution Frame (AMDF) becomes an important role.




                                                                                                  14
                          Main Distribution Frame (MDF or Main Frame)

1.29 INTEGRATED SERVICES DIGITAL NETWORK (ISDN):
      Abbreviation of integrated services digital network, an international communications
standard for sending voice, video, and data over digital telephone lines or normal telephone wires.
ISDN supports data transfer rates of 64 Kbps (64,000 bits per second).
      There are two types of ISDN:
           Basic Rate Interface (BRI) -- consists of two 64-Kbps B-channels and one D-
              channel for transmitting control information.
           Primary Rate Interface (PRI) -- consists of 23 B-channels and one D-channel
              (U.S.) or 30 B-channels and one D-channel (Europe).
The original version of ISDN employs base band transmission. Another version, called B-ISDN,
uses broadband transmission and is able to support transmission rates of 1.5 Mbps. B-ISDN
requires fiber optic cables and is not widely available.

1.30 NEXT GENERATION NETWORK (NGN)
      PTCL is now a days trying to replace their NOUs with NGN‟s. Next Generation Networking
(NGN) is a term which refers to the technology where a single network is capable of transporting
all information and services (voice, data, video) by encapsulating these into packets. NGNs are
commonly built around the Internet Protocol, and therefore the term “all-IP” is also sometimes
used to describe the transformation towards NGN. The IP Multimedia Subsystem, IMS, is a related
concept to NGN. Technologies such as WiFi and WiMAX belong to the NGN area.
      A NGN is a packet-based network able to provide telecommunication services and able to
make use of multiple broadband, QoS-enabled transport technologies and in which service-related
functions are independent from underlying transport-related technologies. It enables unfettered
access for users to networks and to competing service providers and/or services of their choice. It
supports generalized mobility which will allow consistent and ubiquitous provision of services to
users.



                                                                                                15
      the concept behind NGN is a shift away from an era of separate networks (such as
narrowband fixed, broadband fixed, cellular mobile, cable TV), bearing different services (voice,
video, text, data) to multiple devices, e.g. fixed handset, mobile handset, PC. NGN moves towards
a unitary IP-based network in which the common features of the user environment (for example
user preferences, contacts, databases, files and so on) are accessible as the user moves around, say
between home, car and office, or between desk and meeting room. From a regulation point of view
Next generation networks (NGNs) are likely to require next-generation regulation as the problems
of scarcity are replaced by dilemmas of abundance and complexity.
      NGN functional architecture incorporate the following principles.
           Support for multiple access technologies: The NGN functional architecture shall offer
              the configuration flexibility needed to support multiple access technologies.
           Distributed control: This will enable adaptation to the distributed processing nature of
              packet-based networks and support location transparency for distributed computing.
           Open control: The network control interface should be open to support service
              creation, service updating, and incorporation of service logic provision by third
              parties.
           Independent service provisioning: The service provisioning process should be
              separated from transport network operation by using the above-mentioned distributed,
              open control mechanism. This is intended to promote a competitive environment for
              NGN development in order to speed up the provision of diversified NGN services.
           Support for services in a converged network: This is needed to generate flexible,
              easy-to-use multimedia services, by tapping the technical potential of the converged,
              fixed-mobile functional architecture of the NGN.
           Enhanced security and protection: This is the basic principle of an open architecture.
              It is imperative to protect the network infrastructure by providing mechanisms for
              security and survivability in the relevant layers.




                        DP BOX

                                   Secondary cable
                                                             Primary cables
                    Drop wire                 00000                                 00M       Telephone
                                              Cabinet                               00D        exchange
        Telephone                             00000                                 00F




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1.31 TELEPHONE EXCHANGE
      In the field of telecommunications, a telephone exchange or telephone switch is a system of
electronic components that connects telephone calls. A central office is the physical building used
to house inside plant equipment including telephone switches, which make telephone calls "work"
in the sense of making connections and relaying the speech information.
      The term exchange can also be used to refer to an area served by a particular switch
(typically known as a wire center in the US telecommunications industry). It is sometimes
confused with other concepts of telephone geography, such as NPA or area code. More narrowly,
in some areas it can refer to the first three digits of the local number. In the three-digit sense of the
word, other obsolete Bell System terms include office code and NXX.




                                        Manual Service Exchanges

      With manual service, the customer lifts the receiver off-hook and asks the operator to
connect the call to a requested number. Provided that the number is in the same central office, the
operator connects the call by plugging into the jack on the switchboard corresponding to the called
customer's line. If the call is to another central office, the operator plugs into the trunk for the other
office and asks the operator answering (known as the "inward" operator) to connect the call.
      Most urban exchanges were common-battery, meaning that the central office provided power
for the telephone circuits, as is the case today. In common battery systems, the pair of wires from a
subscriber's telephone to the switch (or manual exchange) carry -48VDC (nominal) from the
telephone company end, across the conductors. The telephone presents an open circuit when it is



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on-hook or idle. When the subscriber goes off-hook, the telephone puts a DC resistance short
across the line. In manual service, this current flowing through the off-hook telephone flows
through a relay coil actuating a buzzer and lamp on the operator's switchboard. The buzzer and
lamp would tell an operator the subscriber was off-hook (requesting service).

1.32         Pre-Digital Automatic Exchanges
      Automatic exchanges, or dial service, came into existence in the early 1900s. Their purpose
was to eliminate the need for human telephone operators. Before the exchanges became automated,
operators had to complete the connections required for a telephone call. Almost everywhere,
operators have been replaced by computerized exchanges. A telephone switch is the brains of an
automatic exchange. It is a device for routing calls from one telephone to another, generally as part
of the public switched telephone network.
      The local exchange automatically senses an off hook (tip) telephone condition, provides dial
tone to that phone, receives the pulses or DTMF tones generated by the phone, and then completes
a connection to the called phone within the same exchange or to another distant exchange.
      The exchange then maintains the connection until a party hangs up, and the connection is
disconnected. This tracking of a connection's status is called supervision. Additional features, such
as billing equipment, may also be incorporated into the exchange.
      In Bell System dial service, a feature called automatic number identification (ANI) was
implemented. ANI allowed services like automated billing, toll-free 800-numbers, and 9-1-1
service. In manual service, the operator knows where a call is originating by the light on the
switchboard's jack field. In early dial service, ANI did not exist. Long distance calls would go to
an operator queue and the operator would ask the calling party's number and then dial the number
one by one

1.33 CABINET:
            Cabinet material: high quality stainless steel
            Construction fully corrosion - , aging - , weather - resistant
            Cassette mounting mode facilitates installation of FC and SC adapters
            Each board can be clamped with 12FC or SC adaptors which bevel the face
            Side at 30o so as to ensure the curvature radius of the fiber
            Applicable for normal fiber cables and ribbon optical fiber cables
            Spacious wire arrangement enables all fiber cables and fiber linings to
            Be efficiently guarded

1.34 OPTICAL NETWORK UNIT (ONU)
      Optical network unit is the user side equipment in the GEPON systems. ONU is used with
OLT (optical line transmission) and provides the users with many kinds of broadband services
such as VoIP, HDTV, and video conferences. Optical network unit is economic and high efficient
equipment and play an important role in the FTTx fiber optic network. Optical network unit
converts the fiber optic signal into the electric signal at the user side and enables reliable fiber
optic Ethernet services to business and residential users through fiber-based network infrastructure.




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                  Optical             Fast Data Transmission
                  Network                                            M        Telephone
                  Unit                                               D        Exchange
                                                                     F




                                    Optical network unit

1.35 LIMITATIONS AND PROBLEMS FACED
   Following limitations and problems were faced for conducting this survey

      1. This survey is based on questionnaires. Interviews could not be conducted owing to
         time constraints.

      2. Moreover, as companies tend to keep their organizational information private and
         some people filling out the form could be biased, the interpretations cannot be
         deduced to be correct.




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Description: This document is the analysis report for the survey of PTCL Office.