INTERNSHIP REPORT

PAKISTAN TELECOMMUNICATION COMPANY LIMITED ABBOTTABAD

Submitted by

Department of Electrical and Computer Engineering

COMSATS University Islamabad, Abbottabad Campus

Submitted to
AM Switching Network Operations
Date: 19 September, 2022

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 Acknowledgement
I am thankful to almighty ALLAH, the king of kings and the lord of lords, who
gave me the strength to complete my internship report on PTCL Abbottabad.
I would like to express my special thanks of gratitude to my internship
supervisor, AM Switching Network Operation as well as his team for guiding
me during my internship of 6 weeks at PTCL Abbottabad. I have learned a
lot of new things regarding Telecommunication and Electrical Engineering
from Switching team of PTCL Abbottabad.
I sincerely express my gratitude towards PTCL for providing me this
opportunity. Thanks to PTCL switching department team for giving me such
attention and time. My appreciation also goes to my parents and friends who
helped me in developing my internship report within the limited time frame.
After all Special thanks to COMSATS University for giving me opportunity to
show my abilities in this small effort.

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 Executive summary
Pakistan Telecommunication Company limited is a well-reputed organization
and is a leading organization of Pakistan. Since its establishment, it has
expended its network to great extent. Strong and efficient telecom sector is
the basic requirements of any country. One of these companies is PTCL. No
one can deny the role of PTCL to survive in the current scenario of the world.
Globalization, industrialization and technological advancement are very
necessary to speed up in fast lane. For flexible economy there must be a
Flexible Telecom organization working in flexible and independent way.
The report aims at appraising the working of PTCL, its functions and operation
and also attempts to assess its performance. Certain recommendations are
presented for the potential areas of improvement.

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 TABLE OF CONTENTS
1. Introduction--------------------------------------------------------------------------------------05
2. Company’s History------------------------------------------------------------------------------
06
3. Time Division Multiplexing (TDM)-----------------------------------------------------------
06
4. Next Generation Network (NGN)------------------------------------------------------------
07
5. Communicating with other Exchanges-----------------------------------------------------
09
i. DRS------------------------------------------------------------------------------------------
09
ii. OFS------------------------------------------------------------------------------------------
09
a. Types of Optical Fibers-------------------------------------------------------------
10
b. Applications of Optical Fiber------------------------------------------------------
11
c. Advantages of optical fiber Comunication------------------------------------
11
6. Switching-------------------------------------------------------------------------------------------
11
i. Switching technologies in Abbottabad Interchange----------------------------
11
7. Site Visits-------------------------------------------------------------------------------------------
13
i. Visit to Supply Bazar Network Poles------------------------------------------------
13
ii. Visiting Generator Room--------------------------------------------------------------
14

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 iii. Visiting Rectifier Room-----------------------------------------------------------------
15
iv. Visiting Battery Bank Room-----------------------------------------------------------
15
v. Visiting to SIE Mandian Abbottabad------------------------------------------------
16
8. My Experience------------------------------------------------------------------------------------
16
9. Suggestions And Recommendations--------------------------------------------------------
16
10.Conclusion-----------------------------------------------------------------------------------------
17
11.References-----------------------------------------------------------------------------------------
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1.Introduction
PTCL is the sole land line service provider of Pakistan. PTCL is the giant of Pakistan
telecommunication industry and enjoying the monopoly. This part of the report
contains a brief introduction of PTCL.PTCL is a largest telecommunications provider in
Pakistan. PTCL also endures to be the largest CDMA operator in the country with
0.8 million V-fone customers. The company maintains a leading spot in Pakistan as
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 Fiber Access Network in the major metropolitan centers 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 submarine cables is being expanded to meet the increasing
demand of international traffic. With the promulgation of Telecommunication (Re-

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Organization) Act 1996, the Pakistan Telecommunication Authority was established
as the Telecom Regulatory body.
The basic telephony was put under exclusivity and PTCL was given a seven years
monopoly over basic telephony which ended by December 31,2002. The years 2006-7
in the telecom sector witnessed a phenomenal So far PTCL is the sole land line service
provider of Pakistan. PTCL is the giant of growth in the mobile phone sector in
Pakistan which doubled its subscriber base to 60 million. The Tele density increased
from 26% to 40 helping to spread to benefits of communication technology across the
country. PTCL’s mobile phone subsidiary Ufone’ subscriber base grew by more than
87% from 7.49 million to 14 million. The year also witnessed the entrance of major
telecom companies, most notable China Tele command SingTel, into the market.
Restructuring and re-engineering are in their final stages along with the
implementation of ERP system.
From the end customer’s Perspective, a major initiative was put in place in the shape
of Broadband Pakistan service unveiling as a first step towards providing its customer
with more value added service and convenience. The PTCL not only bringing the
benefit of high speed internet access to subscribers in major cities but will also
generate new revenue streams for future growth. The company also continued to
invest in Infrastructure development and addition of network capacity with a view to
enhance services and to expand its reach across the country.

2.COMpany’s history
At independence in 1947, the Pakistan Telecommunication sector was organized as a
combined P&T Department as it was in India before Partition. In September 1959, the
Minister for Railways and Communications decided that a detailed examination be
made of the working of the Pakistan Posts and Telegraphs Department for bringing
about improvement in the efficiency of the Postal and Telegraph services. The Cabinet
approved this decision and the major step was taken in 1962 to create the Pakistan
T&T Department. Although there was some improvement, but with greater demands
on the T&T for telephones and improvements in service, it was felt that the
telecommunication sector was not meeting the needs of the economy. The World
Bank also held this view. As a result and after reviews, the Government decided to
convert the T&T into an autonomous corporation that was created as PTC by an
Ordinance on 15 December 1990. The establishment of the corporation was an
immediate step in Government’s strategy, which could not be

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supported and financed by Government itself. For this purpose, Government obtained
the services of consortium led by Bear Steams (USA) for study and recommendation,
which result in the promulgation of the Telecommunication Ordinance of July 1995
separating the policy, regulations and operations in the sector. While policy was
reserved for the government, the regulation of the sector was entrusted to the
Pakistan Telecommunication Authority (PTA).

3.Time Division Multiplexing(TDM)

Time-division multiplexing (TDM) is a method of transmitting and receiving
independent signals over a common signal path by means of synchronized switches at
each end of the transmission line so that each signal appears on the line only a
fraction of time in an alternating pattern. This method transmits two or more digital
signals or analog signals over a common channel. It can be used when the bit rate of
the transmission medium exceeds that of the signal to be transmitted. This form of
signal multiplexing was developed in telecommunications for telegraphy systems in
the late 19th century, but found its most common application in digital telephony in
the second half of the 20th century.
Time-division multiplexing was first developed for applications in telegraphy to route
multiple transmissions simultaneously over a single transmission line. In the
1870s, Émile Baudot developed a time-multiplexing system of multiple Hughes
telegraph machines.
In 1944, the British Army used the Wireless Set No. 10 to multiplex 10 telephone
conversations over a microwave relay as far as 50 miles. This allowed commanders in
the field to keep in contact with the staff in England across the English Channel.
In 1953, a 24-channel TDM was placed in commercial operation by RCA
Communications to send audio information between RCA's facility on Broad Street,
New York, their transmitting station at Rocky Point and the receiving station at
Riverhead, Long Island, New York. The communication was by a microwave system
throughout Long Island. The experimental TDM system was developed by RCA
Laboratories between 1950 and 1953.
In 1962, engineers from Bell Labs developed the first D1 channel banks, which
combined 24 digitized voice calls over a four-wire copper trunk between Bell central
office analogue switches. A channel bank sliced a 1.544 Mbit/s digital signal into 8,000
separate frames, each composed of 24 contiguous bytes. Each byte represented a
single telephone call encoded into a constant bit rate signal of 64 kbit/s. Channel
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banks used the fixed position (temporal alignment) of one byte in the frame to
identify the call it belonged to.
Time-division multiplexing is used primarily for digital signals, but may be applied
in analog multiplexing in which two or more signals or bit streams are transferred
appearing simultaneously as sub-channels in one communication channel, but are
physically taking turns on the channel. The time domain is divided into several
recurrent time slots of fixed length, one for each sub-channel. A sample byte or data
block of sub-channel 1 is transmitted during time slot 1, sub-channel 2 during time
slot 2, etc. One TDM frame consists of one time slot per sub-channel plus a
synchronization channel and sometimes error correction channel before the
synchronization. After the last sub-channel, error correction, and synchronization, the
cycle starts all over again with a new frame, starting with the second sample, byte or
data block from sub-channel 1, etc.

4.Next generation Network(ngn)

The next-generation network (NGN) is a body of key architectural changes
in telecommunication core and access networks. The general idea behind the NGN is
that one network transports all information and services (voice, data, and all sorts of
media such as video) by encapsulating these into IP packets, similar to those used on
the Internet. NGNs are commonly built around the Internet Protocol, and therefore
the term all IP is also sometimes used to describe the transformation of formerly
telephone-centric networks toward NGN.
NGN is a different concept from Future Internet, which is more focused on the
evolution of Internet in terms of the variety and interactions of services offered. A
next-generation network (NGN) is a packet-based network which can provide services
including Telecommunication Services and is able to make use of
multiple broadband, quality of service-enabled transport technologies and in which
service-related functions are independent from underlying transport-related
technologies. It offers unrestricted access by users to different service providers. It
supports generalized mobility which will allow consistent and ubiquitous provision of
services to users.
In an NGN, there is a more defined separation between the transport (connectivity)
portion of the network and the services that run on top of that transport. This means
that whenever a provider wants to enable a new service, they can do so by defining it
directly at the service layer without considering the transport layer – i.e. services are
independent of transport details. Increasingly applications, including voice, tend to be
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independent of the access network (de-layering of network and applications) and will
reside more on end-user devices (phone, PC, set-top box).
Next-generation networks are based on Internet technologies including Internet
Protocol (IP) and multiprotocol label switching (MPLS). At the application
level, Session Initiation Protocol (SIP) seems to be taking over from ITU-T H.323.
Initially H.323 was the most popular protocol, though its popularity decreased in the
"local loop" due to its original poor traversal of network address translation (NAT) and
firewalls. For this reason as domestic VoIP services have been developed, SIP has
been more widely adopted. However, in voice networks where everything is under
the control of the network operator or telco, many of the largest carriers use H.323 as
the protocol of choice in their core backbones. With the most recent changes
introduced for H.323, it is now possible for H.323 devices to easily and consistently
traverse NAT and firewall devices, opening up the possibility that H.323 may again be
looked upon more favorably in cases where such devices encumbered its use
previously. Nonetheless, most of the telcos are extensively researching and
supporting IP Multimedia Subsystem (IMS), which gives SIP a major chance of being
the most widely adopted protocol.
For voice applications one of the most important devices in NGN is a Softswitch – a
programmable device that controls Voice over IP (VoIP) calls. It enables correct
integration of different protocols within NGN. The most important function of the
Softswitch is creating the interface to the existing telephone network, PSTN,
through Signalling Gateways and Media Gateways. However, the Softswitch as a term
may be defined differently by the different equipment manufacturers and have
somewhat different functions.
One may quite often find the term Gatekeeper in NGN literature. This was originally
a VoIP device, which converted (using gateways) voice and data from their analog or
digital switched-circuit form (PSTN, SS7) to the packet-based one (IP). It controlled
one or more gateways. As soon as this kind of device started using the Media
Gateway Control Protocol, the name was changed to Media Gateway
Controller (MGC).

5.Communicating with other exchanges

The central PTCL Exchange Abbottabad communicates and connects with other
nearby exchanges via two mediums;
1. DRS (Digital Radio System)
2. OFS (Optical Fiber System)

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 i. DRS:
Digital radio is the use of digital technology to transmit or receive across the radio
spectrum. It is wireless technology. Digital transmission by radio
waves includes digital broadcasting, and especially digital audio radio services.
In digital broadcasting systems, the analog audio signal is digitized, compressed using
an audio coding format and transmitted using a digital modulation scheme. The aim is
to increase the number of radio programs in a given spectrum, to improve the audio
quality, to eliminate fading problems in mobile environments, to allow
additional datacasting services, and to decrease the transmission power or the
number of transmitters required to cover a region.
We will not go into more detail of DRS.
i. OFS:
Optical fibre is the technology associated with data transmission using light pulses
travelling along with a long fibre which is usually made of plastic or glass. Metal wires
are preferred for transmission in optical fibre communication as signals travel with
fewer damages. Optical fibres are also unaffected by electromagnetic interference.
The fibre optical cable uses the application of total internal reflection of light. The
fibres are designed such that they facilitate the propagation of light along with the
optical fibre depending on the requirement of power and distance of transmission.
Single-mode fibre is used for long-distance transmission, while multimode fibre is
used for shorter distances. The outer cladding of these fibres needs better protection
than metal wires.

Most copper wires are now being replaced with optical fiber wires. There are many
advantages associated with optical fiber, such as a very high bandwidth. Theoretically
an optical fiber channel has infinite bandwidth. Optical fiber systems are more secure
than copper wires. Other advantages include noise immunity, low cost, easy
installation, light weight, and very good signal transmission quality. Disadvantages of

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optical fiber are the wires fragility, and harmful effects to the human eye.

a. Types of Optical Fibres:

The types of optical fibres depend on the refractive index, materials used, and mode
of propagation of light.
The classification based on the refractive index is as follows:

 Step Index Fibres: It consists of a core surrounded by the cladding, which has a
single uniform index of refraction.
 Graded Index Fibres: The refractive index of the optical fibre decreases as the
radial distance from the fibre axis increases.
The classification based on the materials used is as follows:

 Plastic Optical Fibres: The polymethylmethacrylate is used as a core material

for the transmission of light.
 Glass Fibres: It consists of extremely fine glass fibres.

The classification based on the mode of propagation of light is as follows:

 Single-Mode Fibres: These fibres are used for long-distance transmission of

signals.
 Multimode Fiber: These fiber are used for short-distance transmission of
signals.

b. Applications of optical fiber:

 Public and private telecommunication lines
 Computer network (LAN, WAN )
 Television distribution network (CATV)
 Military network

c. Advantages of Optical Fiber Communication:

 Economical and cost-effective
 Thin and non-flammable
 Less power consumption
 Less signal degradation
 Flexible and lightweight
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6.Switching
Switching is the process to forward packets coming in from one port to a port leading
towards the destination.
i. Switching Technologies in Abbottabad Interchange:
There are three technologies currently operational in central exchange Abbpttabad.
These are:
1. Alcatel
2. Huawei
3. ZTE

With these different switching technologies PTCL is running its huge network and
providing different communication facilities to its customers.

These switching technologies also have software with them. These software are very
efficiently used to check the status of their MSAGs. With the help of these software,
they can quickly check the real time data of the MSAGs like the AC power status, the
battery charging and discharging status, the temperature of the MSAG and battery,
humidity level inside the MSAG, battery backup, rectifiers status etc. Moreover you
can also monitor the MSAGs of the entire area with the help of the software and can
check whether if AC is off or not. It also gives you an alarm if there is any fault in the
MSAG.
Here is a glimpse of how the software looks like.

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The switching department of PTCL also resolves the problems of customers that
include;
1. Outgoing call blocked
2. Tone not receiving
3. Internet not working
4. Changing the port
5. Creating the port
6. Blocking and Unbloking Numbers
7. Number not showing on Screen

PTCL is a network provider which is using now a days modern techniques to handle all
the problems including standby conditions. In any of the case, if something goes
wrong, they try to resolve the problem through other medium.

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7.Site visits
During my internship of six weeks at PTCL Abbottabad, i have done a couple
of site visits and learnt a lot of new things during every visit.

i. Visit to Supply Bazar Network Poles:

We visited the supply bazar area for resolving the complaints of the subscribers. They
had the complaint that their internet was not working. We went on the site and
checked for the issue. The Optical fiber Cable was broken. We now had to fix the
cable.

Since it is an optical fiber cable, its fixing is not that easy. You first have to peel the top
layers without breaking the Optical fiber. Once that is done, we clean the Optical fiber
cable with the help of alcohol pad, so as to remove any dust particles. Then we
properly cut the optical fiber at the proper angle with the help of fiber cleaver.
An image of cleaver is shown below.

Once the wires are cut properly, we splice the two wires together with the help of the
splicing machine. It is used to create bonding between two optical fibers by

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combining them. In fusion splicing a machine is used to precisely align the two fiber
ends then the glass ends are "fused" or "welded" together using some type of heat or
electric arc. This produces a continuous connection between the fibers enabling very
low loss light transmission. The splicing machine is shown below.

ii. Visiting Generator Room:

During my internship at PTCL Central exchange Abbottabad, I was also provided the
opportunity to visit the generator room there. There are two generators in the
generator room, one is the main generator(400 KVA) and the other one is the backup
generator(250 KVA). These generators are used to provide AC power to the Exchange
when there is electricity shortage. These generators start automatically with the help
of relays whenever there is electricity shortage. Image of generator is shown below.

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iii. Visiting Rectifier Room:
During my internship at PTCL Central exchange Abbottabad, I was also provided the
opportunity to visit the rectifier room there. There are two rectifier cabins in the
rectifier room. These Rectifiers converts the 220V AC to -48V DC which is required to
run the Telecommunication Machinery. All the telecom systems run on -48V DC,
that’s why rectifiers are used there. Rectifiers allow current to flow in a single
direction. Rectifiers take alternating voltage and converts it into high quality direct
voltage needed for your telecom equipment. Traditional telecommunications
equipment generally requires DC input power but mains power runs off AC.

iv .Visiting Battery Bank Room:

During my internship at PTCL Central exchange Abbottabad, I was also provided the
opportunity to visit the battery bank room there. Collection and arrangement of
Battery is termed as Battery Bank or shortly BB. Battery Bank consist of few minimum
4 batteries to maximum no. of batteries as required. Battery Bank in telecom industry
is most common for power backup which may need during AC line faulty. Battery
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bank is used to store current of Photo voltaic energy, AC rectified to DC power or
Diesel Generator power. Different Batteries are present there connected in such a
way that they form a Battery Bank. These batteries are for backup purposes when
there is no AC power.

v. Visit to SIE Mandian Abbottabad:

During my internship at PTCL Central exchange Abbottabad, I was also provided the
opportunity to visit the SIE Exchange. The Mandian exchange provides internet
services to the entire area with the help of copper cables while the Central Exchange
Abbottabad deals with optical fiber cable. These The cables consist of long strands of
copper wire, which transmit electromagnetic waves from one place to another. The
technology has been used for telecommunications since the 19th century, originally
for fixed phone lines.

8.My experience
PTCL is a good organization in a way that anybody can join it for his/her long-term
carrier. Overall working environment is comfortable. Management of branch cares a
lot of its employees and considers them as the Asset of PTCL.

So far my learning is concerned, all the employees at branch were quite cooperative.
They helped me to understand the activities to possible extent. Their good attitude
gave me confidence to learn more and to ask if I have any query in my mind. Besides
their ever going activities, they never get irritated by my questioning. I had made an
honest efferent to present the working and operation of PTCL in simplest way. I feel
pleasure that I have really gained a lot during 6 weeks and enjoyed working with
experienced cooperative and intelligent staff.

9.Suggestions and Recommendations

Given below are some suggestions and recommendations:
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  The number of trainee engineers should be increased by increasing the number
of positions available through the one year paid internship program. This way
there will be enough engineers to train summer internees.
 Internees should be given basic hands on training on the different hardware and
software used by the departments.
 Also tasks, such as making databases, should be assigned to every internee, not
just a few.
 PTCL is one of the leading internship providers in the telecommunication field. I
would recommend to increase this ratio more and more on the basis of merit
so that larger number of fresh engineers should avail such opportunities.
 PTCL should provide super computers to different departments of PTCL
especially to Switching department.
 This is the era of Information Technology. The functions and procedures of
the company should be converted from manual to the automatic.
 Should be developing the training and development process of every employee.

10.Conclusion
No doubt PTCL is enjoying monopoly but the time has come when competition will
force Company to change its policies to become favorite telecom service provider in
the market and keep its current place and customer base.
The company maintains a leading position in Pakistan as an infrastructure provider to
their telecom operators and compare customers of the country. It has the potential to
be an instrumental agent in Pakistan’s economic growth. PTCL has laid an optical
Fiber Access Network in the major metropolitan centers of Pakistan and local loop
services have started to be modernized.
The image of PTCL being leading Telecom provider is not good in the eyes of common
customer especially there are lot of complaints about including the bogus local calls in
the monthly bills of various customers. PTCL also provide the detail of local calls made
from any Land Line number which would be provided in Micro level of the customer.
Finally Telephone connection Fault Free within 24 hours in order to maximize the
revenue, as revenue of PTCL sacrifice at the cost of Faulty Telephone, PTCL should
make Customer Care Centers in remote areas.

11.References:
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 Following are the different websites links used for acquiring the data for
completion of report.
 http://www.en.wikipedia.org/
 http://www.slideshare.net/
 http://www.ptcl.com.pk/
 http://www.researchgate.net/
 http://www.pta.gov.pk/

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