Telecom Switching


To provide the students with an opportunity to develop knowledge, skill and attitude in the area of telecommunication switches system with special emphasis on:
• Evolution of Switching System.
• Features of Switching System
• Feature of Switching Network.
• Feature of time Division Switching System.
• Feature of space Division Switching System.
• Feature of two Dimensional Switching System.
• Feature of AT & T 5ESSS central Office Switch.
• Packet Switching.
• Control of Switching System.
• Features of PABX.
• Signaling


Evaluation Switching System; Features of Switching System; Time Division Switching System; Space Division Switching System; Two-Dimensional Switching System; AT & T 5ESS central Office Switch; Packet Switching; Control of Switching System; PBX and Signaling.



1 Understand the concept of evolution of switching system.
1.1 Describe the concept of switching system.
1.2 Mention different types of switching system.
1.3 Describe the principle of message switching system.
1.4 Describe the principle of circuit switching system.
1.5 Describe the register-translator-senders.
1.6 Describe the hierarchy of switching offices.

2 Understand the features of switching system.
2.1 Describe the general trunking diagram of switching system.
2.2 Describe the principle of strowger step-by-step switching system.
2.3 Describe the principle of crossbar system with trunking diagram.
2.4 Describe the principle of electronic switching system.
2.5 Describe the principle of reed-electronic switching system.
2.6 Describe the principle of digital switching system.

3 Understand the features of switching network.
3.1 Describe the principle of switching network.
3.2 Describe the principles of grading.
3.3 Describe the forms and applications of grading.
3.4 Describe the construction of general link system.
3.5 Describe the basic principle of two, three, & four-stage network for link system.
3.6 Describe the theory for calculating the grade of service (GOS) of link systems.
3.7 Describe the principle of strict-sense non-blocking network.
3.8 Describe the sectionalized switching network.

4 Understand the features of time-division switching system.
4.1 Mention the reasons of saving from the allocation of fixed bandwidth to time-varying assignment of differing bandwidth.
4.2 Describe the construction of space and time switches.
4.3 Describe the principles of operation of analog time-division switching system.
4.4 Describe the principle of operation of digital time-division switching system.
4.5 Describe the operation of a digital memory switch.
4.6 Describe the modules of time switch with diagram.
4.7 Describe the operation of concentrators in digital switching subsystem.
4.8 Mention the function of private branch exchange (PBX) switches and digital cross-connect units.
4.9 Describe the operation of time-division telephone switching.

5 Understand the features of space division switching system.
5.1 Describe the operation of graded rectangular, square, triangular, four wire switching matrix.
5.2 Describe the operation of three stages switching matrix.
5.3 Describe the operation of non-blocking three stages switching matrix.
5.4 Describe the operation of folded four wire switches.
5.5 Define the terms pathfinding and pathfinding time.

6 Understand the features of two dimensional switching system.
6.1 Describe the principle of operational of time space (TS) switching matrix with diagram.
6.2 Describe the principle of operation of STS switching structure with diagram.
6.3 Describe the principle of operation of TST switches structure with diagram.
6.4 Describe the operational No. 4 ESS toll switch and system 75 digital PBX.

7 Understand the concept of packet switching.
7.1 Define the term traffic capacity of circuit switched and packet switched system.
7.2 Describe the principle of packet switching with typical packet format.
7.3 Describe the features of large scale network.
7.4 Mention the features of synchronous transfer mode.
7.5 Describe the principle of operation of asynchronous transfer mode (ATM) switches.

8 Understand the concept of control of switching system.
8.1 Describe the sequence of operations of call processing function.
8.2 Describe the timing of signals exchanged for local call in switching system.
8.3 Describe the simplified state transition diagram for local call.
8.4 Describe the operation of serial trunking in the TXE 4 system.
8.5 Describe the operation of system 12 architecture.
8.6 Define the terms reliability, availability and security.
8.7 Describe the complete software for an exchange.
8.8 Describe the method of overload control.

9 Understand the feature of private branch exchange (PBX).
9.1 Describe the basic principle of PBX switching system.
9.2 Describe the architecture of PBX.
9.3 Describe the data transmission and networking of PBX.
9.4 Mention the advantages and disadvantages of PBX for data as well as voice switching.
9.5 Describe the basic principle of private automatic branch exchange (PABX).

10 Understand the concept of Signaling System.
8.14 Define the Common Channel Signaling.
8.15 List the Applications of CCS Signaling
8.16 Describe the Signaling in Cellular Mobile Networks
8.17 Describe the Digital Subscriber Signaling
8.18 Describe the Exchange Carriers Standards Association
8.19 State the Basic Signaling Networks
8.20 Define SS7 Signaling Links.
8.21 Draw and Describe SS7 STRUCTURE (TUP, ISUP, SCCP, TCAP)
8.22 State the Structure of MTP.
8.23 Procedures for Congestion Control ( Congestion Control at Signaling End Points, Congestion Control at Signal Transfer Points)
8.24 Describe the Telephone User Part Messages and Signals (General Message Structure, Signaling Link Selector and Circuit Identification Code).


1 Study the construction and operation of strowager step by step switching system.
2 Study the construction and operation of cross bar switching system.
3 Study the construction and operation of electronic switching system.
4 Study the construction and operation of reed-electronic switching system.
5 Study the construction and operation of digital switching system.
6 Study the operation of sectioanlized switching network.
7 Study the operation of time division switching system.
8 Study the operation of space division switching system..
9 Study the operation of two dimensional (Ts, TST, STS, etc) switching system.
10 Study the operation of AT & T 5ESS central office switch.
11 Study the operation of ATM switches.
12 Study the complete software of PBX switching system.
** Visit telecommunication switching station and prepare a report.


1 Telecommunication Switching Traffic and Networks
– J. E. Flood.
2 Telecommunication and the Computer
– James MARTIN
3 Digital Telephony

Powered BY: BTEB