Introduction to Telecommunication Switching

1. Telecommunication Switching
Networks
ECE437
Dr. Kuldip Pahwa
Prof. ECE Deptt.
M.M. Engineering College,
M.M. University, Mullana(Ambala)

2. Statistical Bandwidth Sharing
• The term Statistical bandwidth sharing is used to denote a form of
statistical multiplexing where the rate of concurrent traffic streams is
adjusted automatically to make optimal use of available bandwidth.
• It also refers to Intelligent Bandwidth or Dynamic Bandwidh sharing.

3. Switching
• Manual
• Automatic
• Electromechanical
• Electronic ( Stored Program Control)
• Space Divsion Switching
• Time Division Switching

4. Network Configurations
• Folded Network
• Non- Folded Network

5. Elements of a Switching System
• A Switching system is composed of elements that perform switching,
control and signalling functions.
• The subscriber lines are terminated at the subscriber line interface
circuits and trunks at the trunk interface circuits.
• Service lines are used for maintenance and testing purposes.
• Junctor circuits imply a folded connention for local subscribers and
the service circuits.
• Line scanning units sense and obtain signalling information from the
respective lines.

6. Elements of a Switching System
• Distributor units send out signalling information on the respective
lines.
• Operator Console permits interaction with the switching system for
maintenance and administrative purposes.
• Direct Control Switching System
• Common Control Switching System

7. Electronic Exchange
• Dial up lines
• ON HOOK-OFF HOOK
• Pulse Touch- Tone Dialling
• Leased Lines

8. Private Branch Exchange
• PBX is a telephone switch that is physically located at a private-end
user location.
• PBX technique uses a technique called time division multiplexing (
TDM) to sample multiple incoming media signals.
• PBX Components:
• Common Control
• Switching Matrix
• Trunks
• Terminals

9. Telephone Networks
• A Telecommunication network consists of the following major
systems:
• Subscriber end systems
• Switching systems
• Subscriber loop systems
• Transmission systems
• Signalling systems

10. Subscriber Loop Systems
• Every subscriber in a telephone network is connected to the nearest switching office by means of
dedicated pair of wires known as Subscriber loop.
• Generally four levels of cabling are used:
• Branch feeder
• Distribution point
• Distribution cable
• Drop wires

11. Switching Hierarchy and Routing
• Three basic topologies are adopted for interconnecting exchanges:
• Mesh
• Star
• Hierarchy
• Routing Methods:
• Right-through routing
• Own-exchange routing
• Computer- controlled routing

12. Transmission Systems
• Radio systems
• Coaxial cable systems
• Optical fiber systems

13. Numbering Plan
• The numbering plan is used to uniquely identify every suscriber
connected to a telecommunication network.
• Subscriber Trunk Dialling (STD)
• International Subscriber Dialling (ISD)
• A numbering plan may be open, semi-open or closed.

14. Charging Plan
• A charging plan for a telecommunication service has three different
charges on a subscriber:
• An initial charge for providing a network connection.
• A rental or leasing charge.
• Charges for individual calls made.
• Charging for individual calls fall under two broad categories:
• Duration independent charging
• Duration dependent charging

15. Signalling Techniques
• The signalling techniques link the variety of switching systems,
transmission systems and subscriber equipments in a
telecommunication network to enable the network to function as a
whole.
• There are three forms of signalling involved in a telecommunication
network:
• Subscriber loop signalling
• Intraexchange or register signalling
• Interexchange signalling

16. Signalling Techniques
• Inchannel signalling is also known as per trunk signalling and it uses
the same channel which carries usre voice or data to pass control
signals related to that call or connection.No additional facilities are
required.
• Common Channel signalling (CCS) does not use the speech or data
path for signalling. It uses a seperate common channel for passing
control signals for a group of trunks or information paths.