Telecom

1. Limitations of Copper
network
 Copper is costlier and scarce material.
 Fault prone.
 Maintenance difficult
 Vulnerable for EMI.
 Limited bandwidth
 LR restricts route length
 Congestion during Expn

2. Advantages of OF Cable.
• Unlimited bandwidth
• Low Loss - 0.5db per km
• Less number of Repeaters
• Electro Magnetic Immunity
• Small size & Light Weight - Easy to
handle
• Greater Safety - No Electric Hazards
• Higher Security

3. Type of OF Cable.
• Single Mode Fibre
• Multi Mode Fibre
• Plastic Optic Fibre

4. Introduction of OFC.
OF Cable is a guided medium, in
which information (voice, data or video)
is transmitted through a glass or plastic
fibre, in the form of light from one end to
other end.

5. Optical parameters.
• Wavelength
• Frequency
• Window
• Attenuation
• Dispersion
• Bandwidth or NA

6. Application of Cable.
• Telecom network
• CP Commn. Network
• Under sea
• High EMI area
• Explosive env. area
• High lightening area
• Military applications

7. PDH
Plesiochronous Digital Hierarchy.
Support large amount of data to transport .
The term “PLESIOCHRONOUS” is derived from
Greek plesio which means near, and chronous, time.
It means, networks works in different state but not
perfectly within network.
Transmission and reception are synchronized but
timing is not
The channel clocks derived from diff master clock
and range is within limit . It called
“PLESIOCHRONOUS” SIGNAL.
PDH signal are neither SYNCHRONOUS nor
ASYNCHRONOUS.

8. VERSIONS OF PDH
There are two version in PDH
namely
 THE EUROPEAN AND
 THE AMERICAN.
They are different Bit rates and
same
EUROPEAN PCM = 30 CHANNELS
NORTH AMERICAN PCM = 24
CHANNELS

9. EUROPEAN DIGITAL HIERARCHY
It uses the TDM technology.
1. 30 Channel PCM = 2 Mbps
2. 2 Mbps x 4 = 8 Mbps
3. 8 Mbps x 4 = 34 Mbps
4. 34 Mbps x 4 = 140 Mbps
5. 140 Mbps x 4 = 565 Mbps

10. EUROPEAN PDH HIERARCHY WITH BIT RATES
MUX BIT RATE PARTS PER
MILLION
CHANNELS
2 Mbps 2.048 Mbps +/- 50 ppm 30
8 Mbps 8.448 Mbps +/- 30 ppm 120
34 Mbps 34.368 Mbps +/- 20 ppm 480
140 Mbps 139.264 Mbps +/- 15 ppm 1920

11. MULTIPLEXING TECHNIQUE
Digital data from multiple streams
are combined called Multiplexing .
Taking one bit from each stream
and followed by other one .
Multiplexer also adds some
additional bits to enable the
reliable.
The additional bit called
“JUSTIFICATION “OR “STUFFING”
bits.

12. 30 Chl Digital Hierarchy
III Order
Mux
480 Chls
IV Order
Mux
1920 Chls
Primary
Mux
30 Chls
II order
Mux
120 Chls
X 4 X 4
2.048 Mbps 8.448 Mbps 34.368 Mbps 139.264 Mbps
X 4

13. FOTS
• FIBRE OPTIC TRANSMISSION SYSTEM.
• It has the following sub system
– DIGITAL MULTIPLEX SUB SYSTEM.
– OPTICAL LINE TRANSMISSION SUB SYSTEM.
– CENTRAL SUPERVISORY SUB SYSTEM
– POWER SUB SYSTEM
– ALARM SUB SYSTEM

14. DISADVANTAGES OF PDH SYSTEM
Bandwidth is limited
To access LO tributary involves
whole process.
No common standard between
vendors.
Only Point to Point configuration.
No provision for NMS

15. WHAT IS SDH?
 SDH is hierarchical set of information
structure to carry the pay load .
 SDH MULTIPLEXING:- A procedure to
adopt multiple LO path layer signals Mux
section layer.
 POINTER:- Defines frame offset value of
a virtual container.
 SDH MAPPING:- The procedure by which
tributary are adopted in to VC at the
boundary of PDH network.

16. ADVANTAGES OF SDH
1. SIMPLIFIED MULTIPLEXING/DEMULTIPLEXING
TECHNIQUES.
2. DIRECT ACCESS TO LOWER ORDER TRIBUTARIES.
3. ACCOMMODATES EXISTING PDH SIGNALS.
4. CAPABLE OF TRANSPORTING BROADBAND SIGNALS.
5. MULTI-VENDOR, MULTI OPERATOR ENVIRONMENT.
6. PROTECTION SWITCHING TO TRAFFIC IS OFFERED BY
RINGS.
7. ENHANCED BANDWIDTH.
8. NMS FACILITY.
9. UNLIMITED BANDWIDTH
10. GROWTH OF THE EXISTING TO THE HIGHER ORDER
SYSTEM IS SIMPLE.

17. SDH BIT RATES
SDH Levels Bit rates in Kbps
STM-1 155520
STM-4 622080
STM-16
STM-64
2488320
9953.28

18. SDH NETWORK ELEMENTS
• The different network elements are
SYNCHRONOUS MULTIPLEXER
SYNCHRONOUS DIGITAL CROSS
CONNECT
REGENERATOR
NMS

19. TYPES OF NETWORK
TOPOLOGY
• STRING/BUS/LINEAR Topology
• RING Topology
• STAR Topology
• MESH Topology

20. DWDM
Tx Rx
MUX DEMUX
OFAW
D
M
W
D
M
λ1
λ2
λ16
TRANSPONDERS
OPTICAL
SIGNALS.
STM-1
STM-4
STM-16
ATM
IP

21. MAIN NETWORK ELEMENTS
1.TRANSPONDER
2.OPTICAL MULTIPLEXER
3.OPTICAL DEMULTIPLEXER
4.OPTICAL AMPLIFIERS
5.OPTICAL ADD DROP MULTIPLEXER
6.OPTICAL CROSS CONNECT
7.OPTICAL REPEATER

22. ADVANTAGES OF DWDM