FTTH GPON Interview Questions


Q. What is FTTH?

Ans. FTTH stands for Fiber to the Home

Q. What is GPON?

Ans. GPON stands for Gigabit Passive Optical Network. A passive optical network (PON) is a network
architecture that brings fiber cabling direct to the home using a point-to-multipoint scheme that enables
a single optical fiber to serve multiple premises & Customers. It’s a fiber optic transmission technology
for Video, Voice and Data services

Q. What is PON?

Ans. PON is short for Passive Optical Network;
PON consists of Optical Line Terminal (OLT),
Optical Network Unit (ONU) and
Optical Distribution Network (ODN)

Q. OLT?

Ans. Optical Line Terminal
OLT converts electrical signal into optical signal

Q. Basic Network Performance?

Ans. Please see the below for understanding.

Q. GPON Network Elements?

Ans.
Optical Line Terminal(OLT)
Active component of GPON network typically located at central office

Passive Optical Network(PON)
Point to Multi-point access

PON Splitter
Splitter to distribute the Optical signal to multiple fibers

Optical Network Terminal(ONT)
Device to communicate with OLT directly.

Q. GPON Work Access Type?

Ans.
This module will combine end-to-end guidelines including: Access, Outside Plant (OSP) & Inside
Plant (ISP) covering all aspects required for implementing a smooth roll-out of the Gigabit-capable
Passive Optical Network (GPON) and all services shall be offered.

Q. What is WDM?

Ans. WDM stands for Wavelength Division Multiplexer
WDM merges multiple wavelengths into one for transmission over single mode fiber optic

Q. What is ONT?

Ans. Optical Network Terminal
Also called ONU Optical Network Unit
ONT converts optical signal in to electrical for Internet, IPTV and Telephone services

Q. What is fiber optic?

Ans. Fiber Optic is thin strand of highly transparent material made of silica glass.
Fiber Optic is a medium in communication technology for signals transmission

Q. Fiber Optic types?

Ans. There are two types of fiber optic,
1 SMF Single Mode Fiber
2 MMF Multi-Mode Fiber


Q. What`s difference between SMF & MMF?

Ans. SMF construction is different than MMF

  • Core diameter for SMF is .9um and core diameter for MMF is 50-62.5um
  • SMF transmits one signal but multiple signals can be transmitted in multimode
  • SMF been used for long distance and multi-mode fiber been used for short distances
  • SMF fiber wavelength ranges from 1310nm to 1625nm and multi-mode fiber wavelength ranges 850nm to 1300nm


Q. Define Fiber Optic construction parts?

Ans. Fiber Optic consists of three parts
1. Core
2. Cladding
3. Buffer Coating

Q. Principle of signal transmission in Fiber Optic?

Ans. Light signal traverses in Fiber Optic on the principle of Total Internal Reflection (TIR)

Q. What are fiber optic test equipment?

Ans. Visual Fault Locator, Optical Power Meter, Optical Time Domain Reflectometer, Fiber Identifier

Q. How to Splice Fiber Optic?

Ans. FSM Fusion Splicing Machine used to make splice between two fibers

  • Take a bear fiber
  • Strip the buffer coating
  • Apply splice protector on fiber
  • Clean with alcoholic wipes
  • Cleave the fiber to cut 90 degree
  • Put fiber in splicer V grooves
  • Similarly prepare other fiber and enter in another splicer V groove
  • Close the splicer V grooves cover
  • Press Set button to make splice
  • After splice joint cover it with protector and put in heater to complete splicing process

Q. What is VFL?

Ans. Visual Fault locator
VFL is a fiber optic testing tool with laser light of visible spectrum 360nm-670nm

Q. OTDR stands for?

Ans. OTDR stands for Optical Time Domain Reflectometer

Q. OTDR works on which principle?

Ans. OTDR works on the principle of back scattering

Q. Which cable used for internet?

Ans. UTP Unshielded Twisted Pair Category-5, Cat-5e, Cat-6, Cat-7

Q. Why Cat-5, Ca-6, Cat-7 cables called twisted pair?

Ans. Because the cables are twisted to reduce electromagnetic interference and cross talk

Q. Define color coding for straight cable?

Ans.

  • Orange White
  • Orange
  • Green White
  • Blue
  • Blue White
  • Green
  • Brown White
  • Brown

Q. What is Router?

Ans. A router is a networking device that forwards data packets between computer networks.
Routers performs the traffic directing functions on the Internet

Q. How to configure Router?

Ans. Open a web browser
Enter router gateway IP given on router 192.168.0.1 or 192.168.1.1 (Depends on router brand)
Login by router default user id & password (User: Admin, Password: Admin or Mentioned on
router)
Enter settings for ISP (Internet Service Provider) user name and password
Change Wi-Fi user name and password on 2.4Ghz and 5Ghz from default (As per customer)

Q. How to configure a router as Access Point (AP)?

Ans. Open a web browser
Enter router gateway IP given on router 192.168.0.1 or 192.168.1.1 (Depends on router brand)
Login by router default user id & password (User: Admin, Password: Admin or Mentioned on
router)
Enter settings to disable DHCP
Change router password from default to different than main router
Change Wi-Fi user name and password on 2.4Ghz and 5Ghz from default (As per customer or
network requirement)

Q. What is ODF?

Ans. ODF stands for Optical Distribution Frame
ODF used for the fiber distribution in an area or building

Q. What is FDH?

Ans. FDH stands for Fiber Distribution Hub
FDH used for the fiber distribution in an area or building

Q. What are type of FDH?

Ans.
Indoor
Outdoor
Wall Mounted
Underground

Q. ONT threshold for GPON?

Ans. It usually depends on network and varies between manufacturers although ideal threshold
13dBm to 27dBm

Q. How to measure optical power?

Ans. Optical Power meter used to measure optical power in unit dBm

Q. Wavelength for OLT transmission and ONT transmission?

Ans.
Wavelength for OLT transmission is 1490nm and 1550nm
Wavelength which ONT transmits is 1310nm

Q. What are type of Optical Connector?

Ans.

SC/PC Connector
LC/PC Connector
FC/PC Connector
ST/PC Connector

Q. SC/APC Adaptor?

Ans

Q. GPON Optical distribution Network Diagram

Q. CAT-6 UTP Cable & Connector


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