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INTERNSHIP REPORT
Pakistan telecommunication company ltd :
The Report is prepared of 3 weeks for PTCL Transmission
Submitted to: (Mam: Pray).
Submitted By: (1) Muhammad Noman
(2) Soofi Mohsin Hassan
(3) Asif Ali Channa
(4) Shams Gul
Department of BS-Telecommunication
University of Sindh Jamshoro

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Table of Contents
Organizational introduction…………………………………….. 3
Introduction and HistoricalBackground of PTCL …………………………… 3
Transmission……………………………………………………….. 5
Optical Fiber ………………………………………………………………………………………6
Optical Fiber Connector ………………………………………………………………………7
Splicing ………………………………………………………………………………………………. 8
Signal …………………………………………………………………………………………………. 9
Channel-Associated Signaling (CAS) ………………………………………………………..9
Common-ChannelSignaling (CCS) …………………………………………………………..9
SynchronousDigitalHierarchy(SDH) ………………………………………………………10
ONU (Optical Network Unit) ……………………………………………………………………. 11
BroadcastDomain ……………………………………………………………………………………39

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ORGANIZATIONALINTRODUCTION
Introduction & Historical Backgroundof PTCL
PTCL is largest telecommunication company of Pakistan. It has reached its
service to almost every part of the country. (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 with more the 2000 exchanges all providing at least the fixed line
network and the dialup internet service.
Whether it is an office in the largest city of Pakistan or a home in a small
village, PTCL is present in every corner of Pakistan to serve its customers
providing several services.
Someof itsservices arenamedbelow:
Broadband
IPTV
EVO
Wireless
Dialup Internet
TelephonePTCL is established since 1947 by establishing Posts and Telegraph’s
Department, proceeding to establishing Pakistan Telegraph and Telephone
Department in 1961, then in 1990-91, it went to become Pakistan Telecom
Corporation, after which in 1996, PTCL became listed in all stock exchanges of

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Pakistan, further in 1998, its subsidiaries of Mobile Services, and Internet
Services started on the name of Ufone and PakNet, coming to the year 2000, it
Finalized its Telecom Policy. It also announced in year 2003, the Telecom
Deregulation Policy, finally in 2006, Etisalat (The Telecom Company of United
Arab Emirates) took over its Management and it is still holding the status of
backbone for country's telecommunication infrastructure despite arrival of a
dozen other telecoms including telecom giants like Telenor, China Mobile,
Wateen Telecom, and others.

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Transmission
In telecommunications, transmission (abbreviation: Tx) is the process of
sending and propagating an analogue or digital information signal over a
physical point-to-point or point-to-multipoint transmission medium, either
wired, optical fiber or wireless. Transmission technologies and schemes
typically refer to physical layer protocol duties such as modulation,
demodulation, line coding, equalization, error control, bit synchronization and
multiplexing, but the term may also involve higher-layer protocol duties, for
example, digitizing an analog message signal, and source coding
(compression).
Transmission of a digital message, or of a digitized analog signal, is known as
data transmission or digital communication.
One transmission is the sending of a signal with limited duration, for example a
block or packet of data, a phone call, or an email.

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Optical Fiber
optical fiber (oroptical fibre) is a flexible, transparent fiber made of high quality
extruded glass (silica) or plastic, slightly thicker than a human hair. It can
function as a waveguide, or “light pipe” to transmit light between the two
ends of the fiber. The field of applied science and engineering concerned with
the design and application of optical fibers is known as fiber optics. Optical
fibers are widely used in fiber-optic communications, which permits
transmission over longer distances and at higher bandwidths (data rates) than
other forms of communication. Fibers are used instead of metal wires because
signals travel along them with less loss and are also immune to
electromagnetic interference. Fibers are also used for illumination, and are
wrapped in bundles so that they may be used to carry images, thus allowing
viewing in confined spaces. Specially designed fibers are used for a variety of
other applications, including sensors and fiber lasers.
Optical fibers typically include a transparent core surrounded by a transparent
cladding material with a lower index of refraction. Light is kept in the core by
total internal reflection. This causes the fiber to act as a waveguide. Fibers that
support many propagation paths or transverse modes are called multi-mode
fibers (MMF), while those that only support a single mode are called single-
mode fibers (SMF). Multi-mode fibers generally have a wider core diameter,
and are used
for short-distance communication links and for applications where high power
must be transmitted. Single-mode fibers are used for most communication
links longer than 1,050 meters(3,440 f t).
Joining lengths of optical fiber is more complex than joining electrical wire or

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cable. The ends of the fibers must be carefully cleaved, and then spliced
together, either mechanically or by fusing them with heat. Special optical fiber
connectors for removableconnections are also available.
Optical fiber connector
An optical fiber connector terminates the end of an optical fiber, and enables
quicker connection and disconnection than splicing. The connectors
mechanically couple and align the cores of fibers so light can pass. Better
connectors lose very little light due to reflection or misalignment of the fibers.
In all, about 100 fiber optic connectorshave been introduced to the market.

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Splicing:
Fiber splicing is the process of permanently joining two fibers together. Splices
are "permanent"connectionsbetween two fibers.
There are two types of fiber splicing, Mechanicalsplicing and Fusion splicing.
MechnicalSplicing:
Mechanical Splices are alignment gadget that hold the ends of two fibers
together with some index matching gel or glue between them, enabling light
to pass from one fiber into the other.
FusionSplicing:
Fusion splicing is the act of joining two optical fibers end-to-end using
heat. The goal is to fuse the two fibers together in such a way that light
passing through the fibers is not scattered or reflected back by the splice, and
so that the splice and the region surrounding it are almost as strong as the
virgin fiber itself. The source of heat is usually an electric arc, but can also be a
laser, or a gas flame, or a tungsten filament through which current is passed.
Fusion splicing is the most widely used method of splicing as well as providing
the strongest and most reliable joint between two fibers.

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Signal
A function that conveys information about the any physical behavior or
attributes of some phenomenon.
Signaling:
In telecommunication, signaling has the following meanings:
1. The use of signals for controlling communications.
2. The information exchange concerning the establishment and control of a
telecommunication circuit and the management of the network, in contrast
to user information transfer.
3. The sending of a signal from the transmitting end of a telecommunication
circuit to inform a user at the receiving end that a message is to be sent.
Channel-associatedsignaling:
Channel-associated signaling (CAS), also known as per-trunk signaling (PTS), is
a form of digital communication signaling.
Definition:
It uses routing information to direct the payload of voice or data to its
destination.
With CAS signaling, this routing information is encoded and transmitted in the
same channel as the payload itself. This information can be transmitted in the
same band or a separate band to the payload.
CAS potentially results in lower available bandwidth for the payload. For
example, in the PSTN the use of out-of-band signaling within a fixed bandwidth
reduces a 64kbit/s DS0 to 56kbit/s.
Securitybenefits: of separating thecontrollines from the payload.
Application: Robbed-bitsignaling.
Common-channelsignaling:
Definition:
Common-channel signaling (CCS) is the transmission
of signaling information (control information) on a separate channel from the

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data, and, more specifically, where that signaling channel controls multiple
data channels.
For example, in the public switched telephone network (PSTN) one channel of
a communications link is typically used for the sole purpose of carrying
signaling for establishment and tear down of telephone calls. The remaining
channels are used entirely for the transmission of voice data. In most cases, a
single 64kbit/s channel is sufficient to handle the call setup and call clear-down
traffic for numerousvoice and data channels.
The logical alternative to CCS is channel-associated signaling (CAS), in which
each bearer channelhas a signaling channeldedicated to it.
SynchronousDigital Hierarchy (SDH)
Short for an Synchronous Digital Hierarchy international standard for
synchronous data transmission over fiber optic cables. The North American
equivalent of SDH is SONET.
SDH is a standard technology for synchronous data transmission on optical
media. It is the international equivalent of Synchronous Optical Network. Both
technologies provide faster and less expensive network interconnection than
traditionalPDH (PlesiochronousDigitalHierarchy) equipment.

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In digital telephone transmission, "synchronous" means the bits from one call
are carried within one transmission frame. "Plesiochronous" means "almost
(but not) synchronous," or a call that must be extracted from more than one
transmission frame.
SDH uses the following Synchronous Transport Modules (STM) and rates: STM-
1 (155 megabits per second), STM-4 (622 Mbps), STM-16 (2.5 gigabits per
second), and STM-64 (10G bps).
Synchronous Optical Networking (SONET) and Synchronous Digital
Hierarchy(SDH) are standardized protocols that transfer multiple digital bit
streams over optical fiber using lasers or highly coherent light from light-
emitting diodes (LEDs). At low transmission rates data can also be transferred
via an electrical interface. The method was developed to replace the
Plesiochronous Digital Hierarchy (PDH) system for transporting large amounts
of telephone calls and data traffic over the same fiber without synchronization
problems.
ONU(Optical NetworkUnit)
An Optical Network Unit (ONU) converts optical signals transmitted via fiber to
electrical signals. These electrical signals are then sent to individual
subscribers. ONUs are commonly used in fiber-to-the-home (FTTH). The ONU
is at the subscriber end and converts the optical signal to whatever the "last
mile" formatis (DSL, Ethernet, etc.).
Broadcastdomain:
A broadcast domain is a logical division of a computer network, in which all
nodes can reach each other by broadcast at the data link layer. A broadcast
domain can be within the same LAN segment or it can be bridged to other LAN
segments.
In terms of current popular technologies: Any computer connected to the
same Ethernet repeater or switch is a member of the same broadcast domain.
Further, any computer connected to the same set of inter-connected
switches/repeaters is a member of the same broadcast domain. Routers and
other higher-layer devices form boundariesbetween broadcastdomains.

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This is as compared to a collision domain, which would be all nodes on the
same set of inter-connected repeaters, divided by switches and learning
bridges. Collision domains are generally smaller than, and contained within,
broadcastdomains.
While some layer two network devices are able to divide the collision domains,
broadcast domains are only divided by layer 3 network devices such as routers
or layer 3 switches. Separating VLANs divides broadcast domains as well, but
provides no means to network these without layer 3 functionality.
Digital Subscriber line Access Multiplexer
(DSLAM)
A digital subscriber line access multiplexer (DSLAM, often pronounced dee-slam) is a
network device, often located in telephone exchanges, that connects multiple customer
digital subscriber line (DSL) interfaces to a high-speed digital communications channel using
multiplexing techniques.[
The DSLAM equipment collects the data from its many modem ports and aggregates their
voice and data traffic into one complex composite "signal" via multiplexing. Depending on
its device architecture and setup, a DSLAM aggregates the DSL lines over its Asynchronous
Transfer Mode (ATM), frame relay, and/or Internet Protocol network (i.e., an IP-DSLAM
using PTM-TC [Packet Transfer Mode - Transmission Convergence]) protocol(s) stack.
The aggregated traffic is then directed to a telco's backbone switch, via an access network
(AN), also called a Network Service Provider (NSP), at up to 10 G bit/s data rates.

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Main Distribution Frame (MDF )
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 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 an insulated 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 each termination block prevents the wires from covering each other's terminals. With
disciplined administration the MDF can hold over a hundred thousand jumpers, with dozens
changed every day, for decades without tangling

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Pulse-CodeModulation
Pulse-code modulation (PCM) is a method used to digitally represent sampled analog
signals. It is the standard form of digital audio in computers, Compact Discs, digital
telephony and other digital audio applications. In a PCM stream, the amplitude of the
analog signal is sampled regularly at uniform intervals, and each sample is quantized to
the nearest value within a range of digital steps.
Linear pulse-code modulation (LPCM) is a specific type of PCM where the quantization
levels are linearly uniform.[5] This is in contrast to PCM using, for instance, A-law
algorithm or μ-law algorithm where quantization levels vary as a function of amplitude.
Though PCM is a more general term, it is often used to describe data encoded as
LPCM.
PCM streams have two basic properties that determine their fidelity to the original
analog signal: the sampling rate, which is the number of times per second that samples
are taken; and the bit depth, which determines the number of possible digital values
that each sample can take.

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Digital Distribution frame
In telecommunications, a distribution frame is a passive device which terminates cables,
allowing arbitrary interconnections to be made.
For example, the Main Distribution Frame (MDF) located at a telephone central office
terminates the cables leading to subscribers on the one hand, and cables leading to active
equipment (such as DSLAMs and telephone switches) on the other. Service is provided to a
subscriber by manually wiring a twisted pair (called a jumper wire) between the telephone
line and the relevant DSL or POTS line circuit.
In broadcast engineering, a distribution frame is a location within an apparatus room
through which all signals (audio, video, or data) pass, with the ability to arbitrarily route and
connect sources and destinations between studios and other internal and external points.
Connections can either be soldered, or made using terminal blocks. Because the frame may
carry live broadcast signals, it may be considered part of the airchain.

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