power plant

Why use negative DC voltage?

Telecommunications - Negative voltages are used as a safeguard against corrosion of the copper lines used in telecommunication systems

Why positive ground in telecom?

Positive grounding has been used in the telecommunications industry for many years, primarily because the grounded positive electrode of a battery bank will corrode at a much slower rate than a grounded negative electrode

It was more efficient because of lower voltage loss over distance (as a % of the operational voltage), smaller-gauge wire requirements

Why is 48V used in telecom?

Telecom networks use -48 volt direct current (VDC) because it's safe, efficient, and can support telecom signals. 

Safety

-48 VDC is considered a safe low voltage, and is accepted by electrical codes 

It's safer than alternating current (AC) systems, which can cause hum, noise, and other issues 

It has a lower risk of electric shock and arc formation in the event of a fault or short circuit 

Efficiency

It reduces power distribution losses, lowering overall energy consumption 

It allows for the use of smaller gauge wires, while still being capable of carrying power over long wire runs 

Support for telecom signals 

It provides enough power to support a telecom signal

It's also suitable for battery backup systems

Other benefits 

It's compatible with various energy storage technologies

It supports predictive maintenance to optimize performance

It's also beneficial to the automotive industry, especially in electric vehicles (EVs)

VRLA stands for Valve Regulated Lead-Acid, a type of rechargeable battery that is also known as a sealed lead-acid battery

Lead-acid cells consist of two plates of lead, which serve as electrodes, suspended in an electrolyte consisting of diluted sulfuric acid. VRLA cells have the same chemistry except that the electrolyte is immobilized

When a cell discharges, the lead and diluted acid undergo a chemical reaction that produces lead sulfate and water. When a cell is subsequently charged, the lead sulfate and water are turned back into lead and acid.

VALVE:-

Safety valve vent plugs shall be provided in each cell. They shall be explosion resistant, self-resealing and pressure regulating type. They shall not allow gas (air) to enter into the cell but shall allow gas to escape from the cell above a certain internal pressure, which does not lead to deformation or other damage to the cell.

The vent plug used shall be explosion resistant and self re-sealing pressure regulating type. Vent

plug shall be such tat it cannot be opened without proper tool.

The valve shall be so designed that it operates at a pressure between 0.14 Kg / Sq. mm to 0.63 Kg/ Sq. mm to release the excess gas and reseal automatically as soon as the gas pressure within the cell drops to atmospheric value.

All the cells shall be subjected to pressure test upto 0.7 Kg / Sq. mm.

The self-discharge rate at room temperature shall not be more than 5 % of the capacity of each battery per month.

Each valve opening shall be covered with flame barrier capable in preventing the ingress of flame into the cell interior when the valve opens and hydrogen / oxygen gas mixture is released.

NeedofD.C.Power supply

Harmonics of A.C may affect the speech signals.

● Relays used in telecom systems are more sensitive to D.C than A.C

● Transistors and I.C.s etc. being unidirectional devices, the use of D.C has become

necessary.

● Arranging standby source to A.C is difficult compare to D.C for which secondary

cells can be used as standby source.

● Nothazardous to human life.

FTTH

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Will by the time of year q

 FTTH - Fiber to the Home 

MPLS

GPON 

GPON stands for Gigabit Passive Optical Network

GPON - DATA MULTIPLEXING

GPON adopts wavelength dividion Multiplexing (WDM), facilitating bi-directionsl communication over a single fiber

OLT

A CATV (Cable Television) overlay circuit is a technique that utilizes an existing fiber optic network, typically for data and internet services, to also transmit CATV signals. This allows cable operators to deliver TV content over the same infrastructure, providing a cost-effective and efficient way to expand their network and offer more services to customers

OLT

Power card

Line card 

Control card

Card no/slot no/ Port 

32 onu

FBSNL TTH enquiry 

18004444

GPON 

Down stream:1490 nm & 1550 nm

Upstream:1310 nm

SPLITTER 

The SC connector has a ferrule size of 2.5mm while the LC features a 1.25mm ferrule which is exactly half the size of the SC connector.

SC, abbreviated for Subscriber Connector, has also been referred to as Square Connector or Standard Connector. It's a popular fiber-optic connector due to its low-cost, durability and simple installation for both point-to-point and passive optical networking.

Fiber Types of Fiber Optic Patch Cord

Single-mode Fiber (SMF): 

Single-mode fibers have small core diameters, such as 9 microns, but they are low-loss optical waveguides used for longer distances and higher bandwidth. SM patch cords are mainly used in telecoms, long-haul networking

Multi-mode Fiber (MMF): 

MM fibers have larger core diameters of approximately 50 or 62.5 µm and support many light modes. It is cost-effective and can transport higher bandwidths through relatively shorter distances compared to optical SMF. MM fiber can transport data over greater distances with most types of applications, like data centers, campus networks, or LANs

What is Fiber Patch Cord?

A Fiber patch cord, also named as a fiber patch cable or fiber jumper, is a fiber optic cable that is terminated with different types of fiber connectors. These fiber connectors allow the fiber patch cord to be quickly connected to an optical switch or other telecommunication devices. Fiber patch cable plays an important role in indoor fiber use such as in data centers, server rooms, or other LAN applications

SC Connector: 

The subscriber connector, also known as SC, is a component with a push-pull arrangement and ceramic ferrule, resulting in high quality and simple usage.

LC Connector: 

The Lucent Connector (LC) is a very small connector that was introduced to replace the SC connectors, employing a ceramic ferrule. It is widely used in high-density applications on account of being small in size and excellent in performance.

ST Connector: 

The Straight Tip (ST) connector has a fast, yet easy engagement and unlock mechanism called bayonet lock, and is suitable for both datacom and telecom applications.

The ST connecter was developed by AT&T shortly after the arrival of the FC. At a glance, they can be mistaken for one another but the ST uses a bayonet fitment rather than a screw thread

FC Connector: 

The Fiber Connector (FC) is also known as the screw-in connections. 

 

1. SC Connector

The SC was developed by the laboratories at Nippon Telegraph and Telephone (NTT) in the mid-'80s, and was one of the first connectors to hit the market following the advent of ceramic ferrules. Sometimes referred to as the ‘square connector’ the SC has a push-pull coupling end face with a spring-loaded ceramic ferrule. Initially intended for Gigabit Ethernet networking, it was standardized into the telecommunications specification TIA-568-A in 1991 and slowly grew in popularity as manufacturing costs came down. Due to its excellent performance, it dominated fiber optics for over a decade with only the ST rivalling it. It remains the second most common connector for polarization maintaining applications. The SC is ideally suited for datacoms and telecoms applications including point to point and passive optical networking.

2. LC Connector

Considered by some to be the modern replacement of the SC connector; its introduction was less successful, in part due to initially high license fees from inventor Lucent Corporation. Also a push-pull connector, the LC utilizes a latch as opposed to the SC locking tab and with a smaller ferrule, it is known as a small form factor connector. Having half the footprint of the SC connector gives it huge popularity in datacoms and other high-density patch applications, as its combination of small size and latch feature make it ideal for densely populated racks/panels. With the introduction of LC-compatible transceivers and active networking components, its steady growth in the FTTH arena is likely to continue.

3. FC Connector

The FC was the first optical fiber connector to use a ceramic ferrule, but unlike the plastic-bodied SC and LC, it utilizes a round screw-type fitment made from nickel-plated or stainless steel. The connector end face relies on an alignment key for correct insertion and is then tightened into the adapter/jack using a threaded collet.

MTP/MPO Connector: 

MTP or MPO (Multi-fiber Push-On/Pull-Off) connectors and connectors used in high-density applications practically always have ribbon fiber cable. These connectors allow us to finish the installation at one time.

An optical fiber is a thin, flexible, transparent fiber that acts as a waveguide, or "light
pipe", to transmit light between the two ends of the fiber. 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.

ADVANTAGES OF OPTICAL FIBER COMMUNICATION
Fiber Optics has the following advantages:

Wider bandwidth: 

The information carrying capacity of a transmission
system is directly proportional to the carrier frequency of the transmitted signals. The optical
carrier frequency is in the range 10^13 to 10^15 Hz while the radio wave frequency is about 10^6Hz and the microwave frequency is about 10^10 Hz. Thus the optical fiber yields greatertransmission bandwidth than the conventional communication systems and the data rate ornumber of bits per second is increased to a greater extent in the optical fiber communicationsystem. Further the wavelength division multiplexing operation by the data rate or information carrying capacity of optical fibers is enhanced to many orders of magnitude.

Low transmission loss: 

Due to the usage of the ultra low loss fibers and the
erbium doped silica fibers as optical amplifiers, one can achieve almost lossless transmission.In the modern optical fiber telecommunication systems, the fibers having a transmission loss of 0.2dB/km are used. Further, using erbium doped silica fibers over a short length in thetransmission path at selected points; appropriate optical amplification can be achieved. Thus the repeater spacing is more than 100 km. Since the amplification is done in the optical domain itself, the distortion produced during the strengthening of the signal is almost negligible.

Signal security: 

The transmitted signal through the fibers does not radiate.
Further the signal cannot be tapped from a fiber in an easy manner. Therefore optical fiber
communication provides hundred per cent signal security.

Small size and weight: Fiber optic cables are developed with small radii, and
they are flexible, compact and lightweight. The fiber cables can be bent or twisted without
damage. Further, the optical fiber cables are superior to the copper cables in terms of storage,
handling, installation and transportation, maintaining comparable strength and durability.

Fiber optics basis 

MULTIPLAY

The triple play service means providing the following service to the customer: -

 Data (Internet)

 Voice (Voice Over IP (VOIP) or digital Phone)

 Video (IPTV, VoD)

IPTV or TVoIP delivers television programming to households via broadband

connection using Internet protocols.

VoD or in general live broadcast and stored broadcasting using video streaming protocols)

PE router

BNG

RPR/MNGPAN/CPAN

OLT

ONT

VPN

IGW

International Gateways were available from six stations viz., New Delhi,

Mumbai, Chennai, Calcutta, Bangalore and Pune. These six nodes  act as International interconnection Gateway points for Internet 

International Gateways in allA1 nodes

International Gateway is connectivity to the ISP of another country to route the packets intended for any host outside our country 

Access network (OLT-CPAN)

Aggregation network (CPAN - MNGPAN-BNG)

BNG+ PE router 

Core network (PE-MPLS)

 inter national Gate way(IGW)

=================================

Functional modules

BNG

BNG is the access network gate way where all types of services/ customers are landed upon

SSSC

SSSC will define the plan. Plan definition like upload/down load speed, threshold redirection limit, FUP top up etc. are

defined in SSSC

AAA

AAA is meant for Authentication/Authorization/ Accounting

Authentication verifies who a user is, while authorization determines what they are allowed to do

LDAP

Lightweight Directory Access Protocol where customer details such as user name, password, aaa policy based on plan etc.

are stored.

SSSS

SSSS is a web portal and is hosting the page for threshold alerts/ FUP Topup and

Password change

Ethernet cable which is used to connect networking devices through UTP cable and end is terminated with RJ45 connector. In UTP cable consist of 4pair or 8 wire of different color that is used to terminate on RJ45 or 8P8C connector. Ethernet cable color coding as standardized by EIA(Electronic Industries association) and TIA(Telecommunication Industry Association) there are two standard EIA/TIA-568-A and EIA/TIA-568-B.

EIA/TIA-568-A

In EIA/TIA-568-A the eight wire are arranged in Green-White, Green,

 Orange-White, Blue, 

Blue-White, Orange,

 Brown-White, Brown.

EIA/TIA 568A Standard Cable Color Code

EIA/TIA-568-B

In EIA/TIA-568-A the eight wire are arranged in Orange-White, Orange, 

Green-White, Blue, 

Blue-White, Green, 

Brown-White, Brown.

EIA/TIA 568B Standard Color Code

An easy way to remember color code is in odd places(1,3,5,7) color with white strip are present.

 Two types of Ethernet cable connection are made using EIA/TIA-568-A and EIA/TIA-568-B standard

Straight-Through cables

Crossover Ethernet cable

=====================================

Customer got IP Address

Types www.gmail.com

DNS Query : Website name to ip address

Packet to internet

Source ip and destination ip

Source port and destination port - socket