RAJIV GANDHI COLLEGE OF ENGINEERING AND TECHNOLOGY DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING TELECOMMUNICATION AND SWITCHING NETWORK

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1 RAJIV GANDHI COLLEGE OF ENGINEERING AND TECHNOLOGY DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING TELECOMMUNICATION AND SWITCHING NETWORK QUESTION BANK UNIT I MULTIPLEXING 2 MARKS 1. Define trunk. 2. What is the function of a communication channel? 3. Mention the different types of communication channels used in telecommunication. 4. What is mean by open wire pairs? 5. What is mean by four wire systems? 6. List out some advantages of open wire pair. 7. Why does open wire is particularly used for rural applications? 8. Mention some disadvantages of open wire pair. 9. Why does open wire is replaced in rural applications? 10. How do the two wire and four wire circuits are interconnected? 11. Draw the diagram of single wire and two wire transmission system. 12. Differentiate between two wire and four wire circuits. 13. What is space division multiplexing? 14. What are the two forms of multiplexing used in telephone network? 15. What is frequency division multiplexing? 16. Why does single sideband modulation is preferred in communication? 17. Mention the various categories of multiplex level in FDM Hierarchy. 18. List out the frequency band of various group of multiplex level in FDM Hierarchy. 19. Draw the systematic diagram of A5 channel bank multiplexer. 20. Mention the function of A5 channel bank multiplexer. 21. Mention the function of sideband filter in A5 channel bank multiplexer. 22. Draw the diagram of LMX group bank multiplexer. 23. Why does LMX group bank require more equipment? 24. Differentiate between A5 channel bank and LMX group bank multiplexer. 25. Mention the function of pilot tones in higher level multiplex signals. 26. What is Time division multiplexing? 27. What is mean by synchronous and asynchronous time division multiplexing? 28. What is T1 carrier system? 29. What is the basic function of regenerative repeater in T carrier system? 30. Mention the function of channel bank in T carrier system. 31. What is the function of 32 channels in T1 like system? 32. What is the need for equalization in wire pair? 33. What is mean pair gain system? 34. Mention the two purposes for which clock recovery is required. 35. Mention the function of CDO. 36. What kind of modulation technique is used by SLM and SLC and why it is preferred? 37. Mention the use of IDLC. 38. What are the two aspects of digital transmission systems?

2 39. What is mean by pulse transmission? 40. Draw the rectangular pulse and its frequency spectrum with duration T. 41. State Nyquist rate for communication theory. 42. Draw the typical pulse response of a bandlimited channel. 43. What is Intersymbol interference? 44. What are the main causes of Intersymbol interference? 45. What is amplitude equalization? 46. What is phase equalization? 47. What is partial response system? 48. How timing inaccuracy does cause Intersymbol interference? 49. How insufficient bandwidth does cause Intersymbol interference? 50. Differentiate between amplitude and phase equalization. 51. What is line coding? 52. Mention some common line codes used for digital transmission. 53. What is the need for line coding in digital transmission? 54. Mention some parameters that are considered to choose a line code. 55. What is level coding? 56. Draw the Unipolar and polar (NRZ) line codes. 57. How direct current (dc) does is restored for unipolar pulses? 58. How does the droop is eliminated during dc restoration? 59. What is bipolar coding? 60. What is Alternate Mark Inversion? 61. Draw the bipolar (AMI) coding pulses. 62. What is mean by bipolar violation? 63. What is the function of T1 terminal lines? 64. What is the function of bipolar violation in T carrier systems? 65. Mention some application of unused code space in bipolar coding. 66. What is differential encoding? 67. Draw the signal for the data sequence using differentially encoding. 68. Draw the signal for the data sequence using differentially encoded diphase. 69. What is coded mark inversion? 70. Draw the signal for using coded mark inversion. 71. List out some features of digital biphase coding. 72. Mention some network which uses digital biphase coding. 73. Draw the signal for using digital biphase line code. 74. Mention some disadvantages of bipolar coding. 75. Differentiate between digital biphase and differential encoding. 76. Define binary N zero substitution 77. What is substitution? 78. What is B3ZS Substitution Rules and tabulate it. 79. What is violation? 80. Define ternary coding. 81. What is multilevel signaling? 82. What is meant by partial response signaling? 83. Give the uses of line coding. 84. What is mean DC wander? 85. What is meant by differential encoding?

3 86. What is the other name for digital biphase coding? 87. Define correlative level encoding. 88. What is meant by feedback equalization? 89. Write notes on bipolar coding with example. 90. Define pair selected ternary. 91. Define ternary coding. 92. Write notes on DS3 MUX. 93. What is meant by power spectrum? 94. Write notes on bipolar violation. 95. Compare the line coding techniques with example 96. Write notes on bipolar selected ternary. 97. Give correlative level encoding with example. 98. Draw the diagram for Direct-current restoration for unipolar pulses. 99. Give the advantages and disadvantage of level coding Mention about the line coding for NRZ What is mean by TDM ring? 102. Why does each node of TDM ring acts as regenerative repeater? 103. Draw the diagram of Time division multiplexing loop How does full duplex connection is established between any two nodes in TDM? 105. What is the function of distinction node in TDM loop? 106. Why star network is not suitable for sharing in loop configuration? 107. List out some features of TDM loop Mention some applications where TDM loops have been used? 109. Why unidirectional bus is preferred for transmission? 110. Draw the diagram of TDM loop with functional mesh and ADMs What is mean by reverse loop? 112. Draw the diagram to represent the use of reverse loop link failures in TDM loops Mention the function of Add drop multiplexer Differentiate between token passing ring and TDM ring List out some examples of dual reverse loop What are the two basic modes of operation of TDM? 117. What is mean by synchronous TDM? 118. What is asynchronous TDM? 119. What is mean by bit interleaving? 120. What is mean by word interleaving? 121. Draw the diagram of bit interleaving and word interleaving of four channel TDM multiplexers What is mean by frame synchronization? 123. Mention some basic means of establishing frame synchronization Differentiate between synchronous and Asynchronous TDM Differentiate between bit interleaving and word interleaving What is mean by SONET / SDH? 127. Draw the SONET system hierarchy What are the specific issues addressed by SONET? 129. What is OAM? 130. Draw the SONET overhead layers 131. What is section OH?

4 132. What is meant by line OH? 133. Define path OH What are the functions of path OH? 135. Draw STS-I frame format What is STS 1 frame? 137. What are the elements in the STS 1 frame? 138. Draw the Representation location of SPE Draw STS-3 frame format What is CRC error? 141. What is mean by frame alignment? 142. Define bit interleaving What is PCM order wire? 144. What is frame alignment? 145. What is meant by out of frame events? 146. Where does the cross connectors are used? 147. Give the advantages and disadvantages of unique line coding Mention the functions of path overhead bytes Mention the functions allocated to 18 bytes of line overhead List out the functions allotted to 9 bytes of section overhead Draw the functional block diagram of SONET multiplexing Define payload envelope 153. What is meant by SPE? 154. What does the STS-1 signal contains? 155. What is the first step in SONET multiplexing? 156. Write short notes on M13 MUX Write short notes on packing OH Give short notes on transport OH insertion Define SONET rings List the SONET network elements What is meant by self-healing ring? 162. Give the types of self-healing ring Define unidirectional PSR Define bidirectional PRS What is ADM? 166. Draw the diagram of (a) Unidirectional and (b) bidirectional rings Draw the UPSR protection switching Draw the Two-Fiber BLSR protection switches Define span switching Draw the four -Fiber BLSR protection switches Give the disadvantages of UPSR List the advantages of BPSR List the disadvantages of BPSR Why does the protection channel is used in SONET? 175. Give the advantages of UPSR What is the major advantage of asynchronous mode of operation? 177. Mention some major disadvantage of asynchronous mode of operation What is mean by Byte synchronous mapping?

5 179. How the byte synchronous mapping does overcome the disadvantage of asynchronous mode? 180. What is the additional feature offered by the byte synchronous multiplexing? 181. Draw the superframe structure of VT2 tributaries What is mean by 31 channel E1 format? 183. Draw the diagram of DS3 payload mapping How many bits are there in the DS3 payload mapping? 185. What is mean by POH? How many bits are there in the POH byte? 186. Draw a diagram to illustrate an example for a SONET superrate mapping When does the stuff opportunity bit contain information? 188. When does the stuff opportunity bit acts as a stuff bit? 189. How many bytes are there in each row of nine row SPE-3C envelope? 190. How many C bits are there in nine row SPE envelope and mention its function What is the need for using scrambler? 192. Draw the diagram of SONET scrambler How does the scrambler is synchronized? 194. What is the operational wavelength for SONET systems? 195. What does the scrambler converts? 196. Mention the data rate and wavelength for OC-1 and OC-3 SONET source Mention the data rate and wavelength for OC-9 and OC-12 SONET source Why does the frame codes A1, A2 and C1 are not scrambled? 199. When does the same date value arise in SONET scrambler? 200. Mention the BER for the optical sections What is mean by payload framing? 202. What is frequency justification? 203. Draw the representative location of SPE What is the exact location of beginning of SPE? 205. What are the pointer bytes used in STS line overhead? 206. Mention the function of pointer bytes in the STS line overhead What are the two significant features of the pointer in SPE frame location? 208. How the location of SPE in the outgoing payload envelope does is specified? 209. Mention the second advantage of pointer in SPE signals What is the function of pointers in SONET structures? 211. What process will be performed if the tributary uses byte synchronous mapping format? 212. What is the need for synchronization of SONET equipments? 213. How many clock pulses are needed to generate and to carry SPE signal? 214. Mention some applications of SPE pointers in SONET architectures? 215. Draw the diagram to show the positive and negative STS-1 pointer operation What does frequency offsets imply? 217. What does bit stuffing introduces in SONET? 218. What is the function of pointer adjustments? 219. What process will be carried if the elastic store begins with empty? 220. What is the function of negative byte stuffing? 221. Mention the function of H3 slot Mention the use of byte stuffing in frequency justification Mention the function of virtual tributaries List out the various tributary types used in SONET.

6 225. List out some of the virtual tributary designation in SONET How many rows and bytes do the STS-1 consists? 227. What is the function of first 3 bytes of each row? 228. What is mean by path overhead? 229. What is mean by transport overhead? 230. Draw the diagram of STS-1 frame format What is the function of 9 rows of 87 bytes in STS-1 frame format? 232. What is mean by section overhead? 233. What is the frame rate for STS-1? 234. How many columns does the STS-3 format consists? 235. Mention how to calculate the STS-1 rate? 236. Draw the diagram of SONET network What is the function of GNE is SONET network? 238. What are the pointer processing aspects of SONET network? 239. Mention the two reasons for which PJE burst occur Justify your answer, whether pointer adjustment affect VT signal and why? 241. Draw the diagram of SPE synchronization circuit What is mean by bit leaking? 243. What is the function of receiver pointer processing block? 244. What is the function of transmitter pointer processing block? 245. Define pointer burst Mention the special feature of pointer based synchronization architecture Mention the need for designing SONET desynchronizers Mention the first function of microprocessor in SONET desynchronizer Differentiate between the SONET synchronizer and desynchronizer Mention the use of elastic store fill level in SONET desynchronizer. 11 MARKS 1. Explain Transmission systems and its types in detail. 2. Explain about FDM multiplexing and modulation in detail. 3. Explain what is TDM and T1-carrier systems in detail. 4. Discuss in detail about pulse transmission and the problems occurring in it. 5. With neat sketch, Explain about the three line coding techniques in detail. 6. With your own input data Explain about Binary 3 Zero and digital bi phase 7. Explain in detail about the Time division multiplexing loops and rings 8. Compare and contrast between FDM and TDM. 9. Explain in detail about SONET OAM with neat sketch. 10. Discuss in detail about SONET multiplexing techniques and rings. 11. Explain in detail about DS3 and E4 payload mapping 12. Discuss in detail about the various SONET optical standards 13. Discuss in detail about payload framing and frequency justification. 14. Discuss in detail about SONET frame formats and SONET networks. UNIT II DIGITAL SWITCHING PART-A

7 1. What is meant by switching? 2. What is TS switching? 3. What is the need for switching? 4. What is TST switching? 5. Define TDM channel. 6. What is meant by inlet memory? 7. What is meant by outlet memory? 8. What is space switch? 9. What is meant by trunk groups? 10. Draw the structure of TST switching. 11. Define Decorrelators. 12. Define complexity. 13. Give the complexity of a TST switching 14. Draw the complexity comparison of STS and TST switching structures. 15. Draw the diagram of TSSST switching structure. 16. What is ESS toll switch? 17. Draw the probability graph of TSSST switch. 18. Draw the diagram of no.4 ESS matrix architecture. 19. What is meant by no.4 ESS matrix? 20. Give the maximum size of no.4 ESS. 21. Draw the probability graph for no.4 ESS matrix. 22. Mention some special features of TDM. 23. Give the complexity of TSSST switch. 24. Give the probability graph of TST switch with non blocking stages. 25. Mention some applications of TDM links. 26. What is the function of switching? 27. Give the example for local and transit traffic switching examples. 28. Give the applications of space division switching. 29. Classify the types of switching based on stages. 30. Define circuit switched traffic. 31. What is meant by multiple stage switching? 32. Define cross points. 33. Draw the 3-stage switching matrix. 34. What is non-blocking switching? 35. Draw the structure of non blocking 3-stage switching matrix. 36. Give the cross-point requirement of 128 non-blocking switches. 37. Give the total number of cross-points NX required by a 3 stage switch. 38. What is utilization efficiency? 39. What is network traffic? 40. Define pathfinding. 41. Give the conditions for non blocking switching. 42. Define channel switched traffic. 43. When does a worst case situation blocking occurs? 44. Give the equation for a strictly non-blocking operation of a 3 stage switch. 45. Give the equation for a minimum no of cross-points in 3 stage nonblocking switch. 46. Give some example for crosspoint requirement of nonblocking switching. 47. Give the advantages of multiple stage switching.

8 48. Give some advantages of single stage switching. 49. How does the utilization efficiency is increased? 50. Differentiate between single stage and Multi stage switching. 51. Define TDM. 52. What is meant by space division switching? 53. Mention the different types of switching. 54. Define analog TDS. 55. Define digital TDS. 56. Draw the structure of analog TDS. 57. What are the two cyclic control stores? 58. Draw the structure of time and space division switching. 59. What is digital memory switch? 60. Draw the diagram of time slot interchange operation. 61. What is meant line interface? 62. Define switching bus. 63. What is meant by time division control? 64. What are basic requirements of TDM? 65. Give the advantages of TDM. 66. Give the disadvantages of TDM. 67. What is the maximum number of channels C that can be supported by the simple memory switch? 68. What are the advantages of DTDS? 69. What is digital memory switch? 70. Tabulate the cross point requirements of non blocking switches. 71. Draw the diagram of four wire connection through four stage switch. 72. Draw the structure of sequential wires/random read 73. Draw the structure of random wires/ sequential read 74. How the time stages memories can be controlled 75. Mention some applications of ATDS. 76. What is digital switching? 77. What is dsl? 78. What is meant by isdn? 79. What is meant by zero loss switching? 80. What is meant by digital PBX? 81. What is meant by loaded wire? 82. What is meant by unloaded wire? 83. What is meant by edl? 84. What is instability problem? 85. Define BORSCHT. 86. What are the factors involved in BORSCHT? 87. Mention how to reduce the instability problem. 88. Define conferencing. 89. What is Conferencing Bridge? 90. Define slic. 91. What is digital switching? 92. Draw the structure of 4-wire digital switch with 2 wire analog interfaces. 93. How echo can be eliminated in longer circuits?

9 94. What is Digital Cross connect System hierarchy? 95. Give the advantages of conferencing. 96. Give the applications of BORSCHT. 97. Differentiate between loaded wire and unloaded wire. 98. How echoes and singing can be eliminated in 4-wire circuit? 99. Give the applications of digital switching Why does digital switching came in analog environment? 101. What is a digital system? 102. What is a cross connect system? 103. Give the function of Digital Cross connect System Draw the manual cross connect system What is channel bank? 106. What are the main functions of cross connect? 107. What are the major features of Digital Cross connect System? 108. What is local switching system? 109. Define automatic record keeping What is meant by remote and rapid provisioning? 111. Draw the electronic digital cross connect system What is meant by automated test access? 113. What are two types of network traffic? 114. What is consolidation? 115. Define segregation Draw the diagram of consolidation and segregation Draw the schematic diagram of consolidation Define Digital Cross connect System Mention the major function of a manual cross connect frame What is the purpose of Digital Cross connect System 3/3? 121. Define integrated ccs Give the advantages of Digital Cross connect System What are applications requirement of integrated ccs? 124. Draw transposition of data in concatenated time slots Differentiate between consolidation and segregation What is the need for designing public telephone network? 127. Define cross point array List out the techniques used to evaluate blocking probabilities Define blocking probabilities What are the types of blocking probabilities? 131. Draw the nonblocking 3 stage switching matrix What is lee graph? 133. Draw the probability graph of 3-stage network Give the probability of blocking for a 3 stage network Mention the blocking probability B, when any one of n parallel link is used Give the probability of blocking for a 3 stage network.in terms of inlet utilization Draw the five stage switching network What is PBX switches? 139. What is meant by jacobaeus blocking probability? 140. Define TTL.

10 141. Define ISP What is the busy time percentage of residential telephone? 143. What is the busy time percentage of business telephone? 144. What is meant by decorrelating process? 145. Why does the switch is partitioned into sub groups? 146. Why does the PBX users experience high blocking probability? 147. Draw the structure of four- wire switches Give the give the probability of blocking for a 3 stage network using jacobaeus 149. Why does the individual blocking probability are dependent? 150. Mention some special features of digital switches What is a 2-D switching? 152. What is meant by TSM? 153. What is the need for preferring STS and TST switching? 154. What is the need for switching? 155. What is multiple stage time switching? 156. What is the basic function of the time state? 157. Draw the schematic diagram of TS switching Give the implementation complexity of TDSF 159. Define space switching 160. What is multiple stage space switching? 161. What happens when the individual stage in STS switching is non blocking? 162. Mention how to determine the implementation complexity of STS switching Define bit interleaving How the total number of memory bits for the space stage control store is determined? 165. Draw the block diagram of STS switching structure Draw the probability graph of STS switch with nonblocking stages Draw the probability graph of TST switch with nonblocking stages What is the function of inlet memory in TST switches? 169. What is the function of outlet memory in TST switches? 170. Give the blocking probability of TSSST switch Draw the complexity comparison of STS and TST switching structures for a blocking probability of Give the implementation advantages of TST over STS 173. Write the general expression of blocking probability for a TST switch with non blocking individual stages Mention the factors on which the complexity depends on Compare the cross point requirements of STS and space switch design What is meant by SDS? 177. Draw the 4-wire connection through 4-stage switch What is meant by graded switching? 179. What is inter grouping switching? 180. What is a 4 wire switch? 181. What is meant by folded 4 wire switches? 182. What is mirror image path? 183. What is meant by folded operation? 184. Give the advantages of folded wire What is a junctor?

11 186. What is the function of line decoder / demultiplexer? 187. What is the need for path finding? 188. Define path finding times What is meant by independent probability? 190. What is a switch matrix control? 191. Draw a structure of switch matrix control with output associated Draw a structure of switch matrix control with input associated What is meant by output associated control? 194. Give the functions of input associated control line Give the draw backs of input associated control line Where does the data selector/multiplexer has been used? 197. Mention the total no of bits required to specify connection configuration Mention the two ways used in cross point selection How does the multiple stage switches are used? 200. Mention some needs for frequency adjustments Define ESS Give the examples of local and traffic switching Mention the basic function of a switch Give the different types of connection of switching What are the switching categories for voice circuits? 206. What is the most commonly used switching function? 207. Define tandem and mention its functions Define grading Define PABX Draw the rectangular crosspoint array Draw the graded rectangular switching matrix Mention the basic need for designing ACD When does the limited availability exists in space division switching? 214. What is intragroup switching? 215. What are the three parts of a national number? 216. Mention an example for graded switching matrix Define non blocking switches Why does the graded switching matrix is used to access large trunk groups? 219. Why does grading is used in individual switching stages? 220. What does the dashed lines in a two matrix structure indicates? 221. Mention an example for the two sided square matrix Mention the process required before setting connection between input i and j Mention the need for establishing two separate connections for each service request Why sampling rates are preferred in analog TDS? 225. How does the control memory in TS switch in implemented? 226. Define signaling Give the basic scheme of common channel signaling What is meant by typical ccs signaling message format? 229. What are the 3 types of signaling units in ss7? 230. Draw the architecture of ss Define bit stuffing Draw the frame format of message signal unit and link status signal unit.

12 233. Draw the frame format fill in signal unit and control subfields Define SCCP What is Signal transfer point? 236. Draw the frame format of single unit message Write the five control field of ss What is the function of network management? 239. Give the level 3 signaling network functions Mention the functions involved message handling What is the architectural principle of ss7? 242. Compare inchannel and common channel signaling What are the signaling techniques? 244. What are the 3 forms of signaling involved in telecommunications? 245. Mention the uses of different types of signaling Mention the characteristics SS List out the elements of Signaling system Mention the two types of error control units defined in SS Compare basic method and preventive cyclic retransmission method of error control Differentiate between SP and STP. PART-B 1. Explain about TST switching and No.4 ESS toll switch. 2. Write in detail about multiple stage switching, with neat diagram. 3. Define TDM switching? Explain its types in detail. 4. Explain about digital switching in an analog environment. 5. With a neat sketch, explain in detail about digital cross connect systems. 6. Discuss in detail about the two types of blocking probabilities. 7. Explain in detail about STS and TST switching. 8. Write notes on folded 4 wire switch and path finding. 9. Explain in detail about switching functions and space division switching. 10. Explain in detail about elements of SS7 signaling. UNIT 3 NETWORK SYNCHRONIZATION CONTROL AND MANAGEMENT PART-A 1. What are the requirements for synchronization of transmission systems? 2. Why the T1 source data does includes minimum density of 1 s? 3. Differentiate between T1 source data and other line codes. 4. What is the need for network synchronization? 5. Mention some reasons for performing network planning. 6. What is meant by network planning? 7. What are the processes involved in network planning? 8. Why does all digital systems require a frequency source? 9. What is the need for using oscillators in both transmitter and receiver? 10. What is PLL? 11. How does PLL is used for synchronizing transmitter and receiver? 12. What is the function of phase detector?

13 13. Draw the diagram of phase-locked loop clock recovery circuit. 14. What is the function of VCO in clock recovery circuit? 15. What is the function of line clock in clock recovery circuit? 16. What is the need for inserting artificial transitions during clock extraction? 17. What is meant by clock instability? 18. Why does the frequency acts as an important aspect of clock instability? 19. What is a clock wander and jitter? 20. Mention some main sources of clock instability. 21. Mention some reasons for not using low pass filter in clock stability. 22. Write about the use of narrow filters causes clock instability? 23. How the VCO instability does causes clock instability? 24. Mention the important consideration in digital transmission design. 25. How does more number of regenerative repeaters causes difficulty in tracking? 26. Define Jitter. 27. How the PLL is used to measure the jitter? 28. Why the VCO ignores the short term jitter? 29. What happens if no signal is passed through the high pass filter? 30. Draw the circuit for measurement of timing jitter. 31. How does the very low frequency jitter can be measured? 32. What is high frequency jitter? 33. What is meant by phase jitter? 34. Draw the diagram of phase jitter measurement through variance. 35. How to measure the phase jitter through the measurement of variance of clock cycles. 36. What does the term power means in the physical sense jitter? 37. List out some jitter and wander specifications of a DS1 customer interface. 38. What is a systematic jitter? 39. How the accumulated jitter has been removed? 40. Why the jitter is dependent on the data patterns? 41. When does the phase ramp occur? 42. What does the last repeater experiences in systematic jitter? 43. What does the phase ramp represents and mention its effects. 44. What is an elastic store? 45. How does the bit change occur in long repeated transmission link? 46. Draw the model of systematic jitter in a string of regenerative repeaters. 47. Draw the diagram of jitter removing regenerative repeater. 48. Mention how to implement elastic store using series parallel converter. 49. Mention how to implement large elastic stores using FIFO buffer. 50. Mention the limitations of repeater count used in jitter removal. 51. What is meant by timing inaccuracy? 52. What is meant by autonomously timed switch? 53. What is meant by frequency offset? 54. Draw the diagram showing the connections between autonomously timed digital switches. 55. Mention the effects of over flow due to variations in write / read rates. 56. What is meant by controlled slip? 57. What happens when average rate R2 is greater than R1? 58. What happens when average rate R2 is less than R1?

14 59. Define slip. 60. What are the effects of uncontrolled slips? 61. Differentiate between the controlled and uncontrolled slips. 62. Draw the diagram of elastic store operation with one frame memory. 63. What process is carried out when a slip occurs in a controlled slip method? 64. Why the slips are allowed to occur in prescribed manner? 65. What does the timing diagram of elastic store with one frame memory depicts? 66. When does the double write causes frame overwrite operation? 67. Mention the advantage when elastic store and time switching functions are combined. 68. Mention the attractive feature of using inlet memory. 69. What is meant by justification? 70. Draw the functional diagram of M12 multiplexer. 71. Mention the potential problem experienced with the elastic store. 72. Draw the diagram of elastic store with two frame memory. 73. Mention the time and frame rate difference between the two slips. 74. Mention the uses of pulse stuffing. 75. List out the features of asynchronous multiplexing. 76. What is meant by waiting time jitter? 77. Give some examples of overhead bits. 78. How does the waiting time jitter caused by the overhead bits can be eliminated? 79. What is meant by mapping jitter? 80. Give an example on how to eliminate the mapping jitter. 81. Draw the diagram to show the mapping jitter of ITU E1 in E2 signal. 82. Why the elastic store does not perfectly reconcile with E2 master frame? 83. Why does the waiting time produced by pulse stuffing is difficult to deal with? 84. Why does the sub channel output clock must be derived independently? 85. Draw the functional diagram of M12 demultiplexer. 86. How does the output clock of M12 demultiplexer are generated? 87. Draw the diagram of time interval errors produced by adjusting waiting times. 88. Why does the jitter cannot be eliminated completely? 89. How does the waiting time jitter occurs? 90. Mention the ratio on which the waiting time jitter depends on. 91. Draw the frame format of DS Draw the frame format of DS1C digital signal. 93. Mention how to reduce the waiting time jitter. 94. Draw the frame format of second level digital signal ITU-T (E2). 95. Draw the diagram to show the waiting time jitter dependence on justification ratio. 96. Draw the diagram to show the relationship between the line length and number of bits. 97. Mention the requirements of elastic store size. 98. List out the two purposes that the elastic store serves. 99. Mention the additional purposes of using elastic store Mention the condition of stuffing when the elastic store is more than half full What is the need for synchronization of digital switch and link? 102. When the unsynchronized interface occurs? 103. What is meant by network synchronization? 104. What are the basic reasons for paying assiduous attention to timing requirement? 105. Why the synchronizing of private network is more difficult?

15 106. What are the types of approaches used in synchronizing digital network? 107. Why does the synchronization process is vital for digital transmission? 108. How the network is synchronized using Plesiochronous method? 109. Why the Plesiochronous method is simple to implement? 110. How the Plesiochronous method is used in large network? 111. What is meant by pulse stuffing? 112. What is meant by networkwide pulse stuffing? 113. What is the need for separate pulse stuffing? 114. Draw the diagram of networkwide pulse stuffing using TDM switch Why the stuffing complexity is more expensive in digital network? 116. What are the other problems occurs in networkwide pulse stuffing? 117. What is meant by mutual synchronization? 118. Draw the diagram of mutual synchronization Mention the main attractiveness of mutual synchronization What are the disadvantages of mutual synchronization? 121. Mention some real time examples where the mutual synchronization is being used Compare Plesiochronous and networkwide pulse stuffing method Differentiate between Plesiochronous and mutual synchronization method Mention some real time examples where the Plesiochronous is being used Mention the frequency stability status of mutual synchronization What is meant by network master? 127. How the single master clock provides network synchronization? 128. Draw the diagram of network master synchronization What is meant by reference frequency? 130. What is meant by GPS? 131. What is the function of switching node? 132. Why the switching system uses GPS system? 133. Draw the diagram of synchronization link What are the two types of synchronizing links? 135. Draw a diagram to show an example for simplified pulse stuffing Draw the diagram of bilateral system What is the function of master reference? 138. Mention the drawbacks of network master synchronization What is meant by master slave synchronization? 140. How does the disadvantage of network master can be overcome? 141. What is meant by destuffing? 142. What is the process of master slave in master slave synchronization? 143. Why slip does not occur in master slave synchronization? 144. Why does short term frequency differences occurs between some nodes? 145. What is the purpose of providing backup clocks in all switches? 146. Draw the diagram of master slave synchronization Give a real time example for master slave synchronization Distinguish between network master and master slave method Mention some advantages of master slave synchronization Mention some disadvantages of master slave synchronization What is meant by packet switching network? 152. Differentiate between circuit switching and packet switching network.

16 153. Define packets Define packetization What does the transmission link carry in between the blocks? 156. How the elastic store avoids loss of data in packet switching network? 157. Justify your answer on whether slips will occur in idle codes? 158. Mention some advantages of using packet switching network Mention some disadvantages of using packet switching network What is the need for measuring the quality of timing signals? 161. Define cells of data Define TIE Define MTIE Define time variance Define time deviation What is meant by clock imperfection? 167. Mention the different types of clock imperfections Why the stable reference is needed for long observations period? 169. Give the TIE produced by measuring perfectly stable inaccurate timing signal Give the TIE produced by short term instabilities How the TIE will be, when the signal under test contains both instability and frequency offset? 172. Draw the diagram of TIE and MTIE for various clock imperfections Draw the diagram of maximum time interval error example Mention the use of second order differences in time variance Differentiate between time variance and time deviation What type of synchronization is used in US network synchronization? 177. Why does the US synchronizing architecture changed to Plesiochronous method? 178. Draw the diagram of North American network synchronization What are the different levels of timing hierarchy? 180. Mention the clock quality of different types of stratum What is meant by primary reference source? 182. Mention about the accuracy status of stratum 1 clock What is the need for dividing private network into synchronization regions? 184. Mention the accuracy requirements of stratum clock What are the requirements of holdover mode of stratum 2 and stratum 3? 186. What are the requirements of holdover mode of stratum 4? 187. Mention the effects of abrupt switchover in stratum 4 nodes How does the stratum 2 responds to the failure of complete nodes? 189. How does the stratum 3 responds to the failure of complete nodes? 190. What is meant by UTC? 191. How to determine the maximum input channel rate accommodated by M12 multiplexer? 192. How to determine the minimum input channel rate accommodated by M12 multiplexer? 193. Mention the types of UTC based navigation system used for verification Why AT&T uses global positioning system? 195. Draw the AT&T synchronization architecture Draw the diagram of output of primary reference source List out the significant features of AT&T synchronization architecture Compare the slip rate of stratum 3E with stratum 3 clocks in holdover conditions.

17 199. Compare the free run accuracy of various types of stratum Mention the advantages of stratum 4 timing quality What is meant by connection control? 202. What is meant by network control? 203. What is the fundamental concept in network control? 204. What is a state transition diagram and mention its purpose? 205. When does the state transition diagram effectively define communication process? 206. Draw the state transition diagram for clock synchronization process Mention the purpose of clock synchronization process Draw the transition diagram of synchronization process involving framing process Draw the originating subscriber diagram of telephone connection process Why the message exchange processes need synchronization? 211. What are the steps involved in the telephone connection process? 212. What happens when the switch recognizes off hook signal? 213. What is meant by busy tone? 214. What is meant by ringback tone? 215. What does the high level maintainability ensures? 216. What is meant by automated faulty control procedure? 217. How the circuit is recovered from malfunction? 218. Define protocol How does a talker indicate his end of transmission? 220. How the voice users begins the connection between end offices Differentiate between busy tone and ring back tone List out the function of dependability criterion? 223. Draw the switch control diagram of telephone connection process List out the basic procedures followed to establish a connection Mention the parameters defined by the protocol What is meant by network management? 227. What is the basic goal of network management? 228. What are the main considerations of network management? 229. Define routing control Why does direct routes are mostly preferred? 231. What is the drawback of direct routing? 232. What does the centralized network control provides? 233. What is meant by flow control? 234. What happen if there is no flow control in a network? 235. Draw the generalized performance of uncontrolled network What happens if the load is increased in the network? 237. What happens if heavy traffic exists in the network? 238. Mention some needs for having flow control in network Define code blocking Why the receiving terminal uses a reverse channel? 241. Mention the two types of two types of trunk circuit How does the trunk directionalize help network during heavy load condition? 243. What is meant by alternate routing? 244. List out the functions of network management centres Differentiate between one way trunk and two way trunk circuits.

18 246. Mention the special feature of two way trunks Why the alternate routing becomes undesirable? 248. How does the flow control is useful during natural disasters? 249. Mention the two purposes serving by the principle of giving preference Mention the more desirable mode of operation from throughput point of view. PART-B 1. Discuss in detail about PLL and clock Instabilities. 2. With neat sketch, explain about Jitter measurement and systematic jitter. 3. Explain in detail about slips and asynchronous multiplexing. 4. Discuss in detail about the waiting time jitter. 5. Write in detail about Plesiochronous and mutual synchronization 6. Discuss in detail about network master and master-slave synchronization. 7. Write in detail about packetisation and network timing performance measurements 8. Explain in detail about U.S network synchronization. 9. Discuss in detail about network control and Hierarchical synchronization processes. 10. Discuss in detail about network management. UNIT IV DIGITAL SUBSCRIBER ACCESS PART-A 1. Define ISDN. 2. What are the four basic transmission technologies used in local digital access? 3. How does the copper wires are used in voice and data transmission? 4. Define MMDS. 5. Define CCS. 6. Mention some of the telecommunication standards. 7. Mention the types of telecommunication networks. 8. List out the features of ISDN B channels. 9. List out the features of ISDN D channels. 10. What is the function of U and R interface? 11. Mention the function of T and S interface. 12. Draw the basic rate interface architecture. 13. What is meant by basic rate access? 14. What is meant by primary rate access? 15. Draw the diagram of ISDN circuit access. 16. What is B channel and D Channel? 17. What is ISDN access line? 18. Define circuit switched digital network. 19. Define packet switched digital network. 20. Draw the diagram to show the basic rate and primary rate access to ISDN. 21. Differentiate between NT1 and NT Mention the use of terminal equipment TE Mention the function of terminal adapter. 24. Mention the use of terminal equipment TE Differentiate between TE1 and TE What is meant by S/T interface?

19 27. What are the most significant aspects of S/T interface? 28. Draw the S/T frame structure. 29. List out the bit specifications of S/T interface. 30. Draw the diagram of alternate space inversion code. 31. Mention the specification of 10 bits from NT to TE terminal. 32. What is the purpose of using L bit at the end of each data block? 33. What is the purpose of existence of E bits in NT to TE terminal? 34. How does the multiple station access to D channel is controlled? 35. What are the two levels of priority defined for accessing D channel? 36. What is meant by ISDN U interface? 37. Draw the diagram of S bus connections. 38. Define TCM. 39. What is meant by ping pong transmission? 40. Mention the advantage of TCM transmission. 41. Mention the disadvantage of TCM transmission. 42. Draw the ISDN DSL block diagram. 43. What is ISDN D channel protocol? 44. Mention the function of hybrid and echo cancelor in ISDN transmitter? 45. Draw the super frame structure of ANSI U interface. 46. List out the ITU-T series of D channel protocol. 47. Mention the main function of data link layer. 48. List out the functions of D channel network layer. 49. Mention the dominant limitations of 2B1Q line coding. 50. List out some applications of ISDN. 51. Define digital subscriber loop. 52. What are the special features of DSL? 53. Mention the various types of DSL. 54. Define HDSL. 55. Define ADSL. 56. How does the potential repeater error has been eliminated in HDSL? 57. Mention the special features of ADSL. 58. What is the transmission rate of ADSL subscriber? 59. What is the receiver rate of ADSL subscriber? 60. What are the advantages of ADSL over ISDN access? 61. What are the two versions of ADSL transmission lines? 62. Mention the applications of ADSL. 63. Draw the diagram of ADSL DMT block diagram. 64. Draw the diagram of ADSL network configuration. 65. Mention the ADSL DMT implementation parameters. 66. What is the function of PRS source? 67. What is channel allocation? 68. What is meant by Forward Error Correction? 69. What is meant by IFFT QAM modulation? 70. What is meant by data detection and interleaving? 71. Mention the function of POTS splitter. 72. Mention the purpose of using AGC. 73. Differentiate between IFFT modulation and FFT demodulation.

20 74. List the functions of frequency domain equalizer. 75. Where does the slope / delay equalization is used and mention its function? 76. Define VDSL. 77. Define RADSL. 78. Define PSTN. 79. What is central office and what are its functions? 80. What is the data rate of ADSL? 81. What is the purpose of developing VDSL? 82. What kind of transmission line does the VDSL uses? 83. List out the types of transmission lines used by VDSL for short ranges. 84. What is the maximum downstream rate of VDSL? 85. What is the maximum upstream rate of VDSL? 86. What kind of modulation technique has been used in upstream? 87. Mention the various data rates for VDSL data transport. 88. Mention some advantages of using VDSL. 89. List out the line codes proposed for VDSL. 90. List out the special features of VDSL. 91. Mention the characteristics of VDSL. 92. What are the primary functions of VDSL? 93. List out the applications of VDSL. 94. Compare the features of ADSL and VDSL. 95. Mention the variation in data rate offered by the ADSL. 96. List out the various versions of HDSL. 97. Mention the functions of call control. 98. List out the functions of ITU-T Q.931 protocol. 99. Differentiate between HDSL and VDSL Mention the three factors responsible for ISDN motivation Define DLC What is the general purpose of using DLC? 103. What does the DLC natural mechanism provides? 104. Mention some advantages of DLC What are the unique requirements of DLC? 106. List out the types of DLC system What is the main purpose of DLC? 108. Define UDLC Draw the diagram of UDLC system How does the UDLC interfaces COT and RT? 111. What is meant by COT? 112. What is meant by RT? 113. When does the blocking occurs in UDLC? 114. What are the effects of blocking in UDLC? 115. How many sub-channels are required for an ADSL implementation? 116. Draw the diagram of local exchange UDLC configuration Draw the diagram of remote exchange UDLC configuration Mention the downlink sampling rate of ADSL What is the uplink sampling rate for ADSL? 120. How does the UDLC installations are configured?

21 121. Mention the various varieties of UDLC interfaces Compare the earlier and recent system of UDLC configuration Mention some advantages of UDLC List out the disadvantages of UDLC Mention the applications of UDLC service What is integrated DLC system? 127. What is the main purpose of designing IDLC system? 128. Define IDT Draw the diagram of IDLC system How does the fiber based DLC system interfaces with the switch? 131. How does an IDLC system can be installed in a local telephone distribution network? 132. What is the function of RT in IDLC system? 133. What does the central office switch vendor offers? 134. Mention the process to be performed to originate a call List out the special features of GR303 specification What are the uses of GR303? 137. What is meant by next generation DLC systems? 138. Mention the four basic attributed adhered with GR Draw the diagram of next generation DLC systems What are the other aspects available in NGDLC system? 141. Mention the most important aspect of NGDLC system What are the most desired interfaces used in NGDLC system? 143. What are the other possible digital interfaces used in NGDLC system? 144. What is the function of remote terminal in NGDLC system? 145. What is meant by drop and insert capability? 146. List out the topologies supported by the GR Mention the function of COT in NGDLC system Compare the features of IDLC and NGDLC systems List out the advantages and disadvantages of NGDLC system Mention some applications of NGDLC systems Define hybrid fiber coax systems Define cable TV What is bidirectional amplifier? 154. Define QAM Define TDM Define FTTH Define POTS network What is upstream channel? 159. Define cable modems What are the special features of cable modems? 161. What is channel bandwidth? 162. What are the limitations of cable modem? 163. What is subscriber line? 164. Define CATV What is meant by HFC? 166. Define Interference level Define optical transmission.