Description : Broad Band ISDN handles data rate of about (A) 64 kbps (B) 100 mbps (C) 5.4 mbps (D) 2.048 mbps
Last Answer : (A) 64 kbps
Description : What do you mean by numbering and addressing? Draw the ISDN address structure and explain how the addressing works?
Last Answer : Numbering and Addressing: In telephone and data networks, the end equipments are more often single units than multiple devices units like PABX or LAN. Historically, a telephone, a computer, or a ... as reference point may also be addressed by using direct inward dialing (DID) feature.
Description : Explain the working of broad band ISDN.
Last Answer : BISDN Configuration: Fig. shows how access to the BISDN network is accomplished. Each peripheral device is interfaced to the access node of a BISDN network through a broadband distant ... consequently, have higher transmission rates and offer more channel handling capacity than ISDN systems.
Description : How speech is transmitted in a digital switching environment using PCM/TDM?
Last Answer : A digital carrier system is a communications system that uses digital pulses rather than analogue signals to encode information. Fig shows the block diagram for a digital carrier system. This digital ... to maintain frame and sample synchronization between the TDM transmitter and receiver.
Description : Common channel signalling______________ (A) Uses the speech or data path for signaling. (B) Does not use the speech or data path for signaling. (C) Needs no additional transmission facilities. (D) Finds it difficult to handle signaling during speech.
Last Answer : (C) Needs no additional transmission facilities.
Description : Example of circuit switching and S&F (Stored and Forward) switching is (A) Telephone and Post of Telegraph (B) Video Signal Post or Telegraph (C) Digital Signal Post or Telegraph (D) None of above
Last Answer : (A) Telephone and Post of Telegraph
Description : The CCITT standard bandwidth for speech is: (A) 20000 Hz (B) 15000 Hz (C) 7000 Hz (D) 3400 Hz
Last Answer : (D) 3400 Hz
Description : SS7 Protocol uses: (A) Out of band signalling. (B) Associated signalling. (C) Speech control signalling. (D) No signalling.
Last Answer : (A) Out of band signalling.
Description : Common channel signalling in SS7 is (A) out band control channel. (B) in band control channel. (C) speech control channel. (D) none of the above.
Last Answer : (B) in band control channel.
Description : Side tone is the speech heard by (A) the receiving subscriber (B) both the receiving and calling subscriber (C) by on looker (D) by calling subscriber
Last Answer : (D) by calling subscriber
Description : In a time multiplexed space switching system, one speech sample appears every (A) 125 micro sec (B) 20 msec (C) 125 msec (D) 1 sec
Last Answer : (A) 125 micro sec
Description : State weather the following statement is true or false for ISDN - Integrated Services Digital Network ISDN is an effort to standardize subscriber services, provide user/network interfaces 2). the goal of ISDN is to form a Local ... C. 1. false, 2. false, 3. false D. 1. true, 2. true, 3. false
Last Answer : A. 1. True, 2. false, 3. true
Description : Explain the basic architecture of digital switching systems. Explain in detail companding.
Last Answer : A simple N X N time division space switch is shown in Fig. The switch can be represented in an equivalence form as a two-stage network with N X 1 and 1 X N switching matrices for the first and ... = Parameter used to define the amount of compression Vout = Compressed output voltage.
Description : Name the switching schemes used in a digital exchange. How call processing takes place?
Last Answer : The different switching systems used are: 1. Strowger Switching System 2. Cross bar Switching. 3. Electronic Switching System Basic Call Procedure: Fig. Shows a simplification ... machine detects an open circuit on that loop and then drops the connections through the switch.
Description : A distributed network configuration in which all data/information pass through a central computer is (A) Bus network (B) Star network (C) Ring network (D) Point to point network
Last Answer : (B) Star network
Description : Which protocols adopted the standards of HDLC (High Level Link Control) protocol? a. X.25 protocol as LAPB (Link Access Procedure Balanced, V.42 protocol as LAPM (Link Access Procedure for ... Services Digital Network) protocol as LAPD (Link Access Procedure on D channel) d. All the above
Last Answer : d. All the above
Description : What is a Modem? What is the need of MODEM in data communication? Explain at least one modulation technique used for high speed modems.
Last Answer : Modems are essentially used to interface digital circuits to transmit information on analogue channels like telephone systems. Modem (from modulator-demodulator) is a device that modulates an analogue carrier ... caused by the lines makes the detection even harder than amplitude modulation.
Description : Classify data networks. Explain with the help of Nyquist theorem, the data rate limitations in PSTN’s. Give an account of modems used in data transfer. Explain their importance and list some of the V-series recommendations.
Last Answer : Classifications of Data Network: Data Networks are classified according to their geographical coverage: Wide area networks (WANs) Metropolitan area networks(MANs) Local area ... V.53 Limits for the maintenance of telephone type circuits used for data transmission.
Description : ARQ is transmitted in the event of: (A) Loss of signal (B) Error in received data (C) Improve reliability (D) During time out
Last Answer : (B) Error in received data
Description : In a time division space switch the size of the control memory is N and its Width: (A)Log10M (B) LogeM (C) LogNM (D) Log2M Where N are the outlets and M the number of data samples
Last Answer : Ans: (It should be 2 log2[N]
Description : Network Layer is used for (A) Breaking up the data in frames for transmission (B) Deal with Error correction (C) Automatic Recovery of Procedure (D) Physical Architecture
Last Answer : (D) Physical Architecture
Description : Which transmission mode is used for data communication along telephone lines? (A) Parallel (B) Serial (C) Synchronous (D) Asynchronous
Last Answer : (B) Serial
Description : Computer to computer communication is: (A) Simplex (B) Duplex (C) Half Duplex (D) Both Duplex and Half Duplex
Last Answer : (B) Duplex
Description : Data from a computer are_______; the local loop handles _______ signals. A) analog; analog B) analog; digital C) digital; digital D) digital; analog
Last Answer : digital; analog
Description : Explain the process of inter-register signalling.
Last Answer : Registers are used in common control exchanges to store and analyze routing data. They are provided on a common basis is a single register provides routing data for a number of speech circuits. Once a call ... it is released and the originating register signals to the next register.
Description : Draw a centralized SPC organization and explain how it works under load sharing operation.
Last Answer : In centralized control, all the control equipment is replaced by a single processor which must be quite powerful. It must be capable of processing 10 to 100 calls per second, depending on the ... both the processors are active simultaneously and share the load and the resources dynamically.
Description : Explain FDM and show how CCITT standards help in building the base band?
Last Answer : Frequency Division Multiplexing: It is the process of combining several information channels by shifting their signals to different frequency groups within the spectrum so that they can be transmitted simultaneously ... of 24 channels were assembled together in one stage of modulation.
Description : What are transmission bridges? How do they help in satisfying the connectivity?
Last Answer : A typical transmission bridge is shown in Fig. The series capacitance and the shunt inductances of the two relays provide a high-pass filter to transmit the AC speech signals, while the relays respond independently to the DC loop/disconnect signals from the calling and called customer.
Description : What are the different ways of designing 100 line exchange using uni selector and two motion selectors? Show at least three variations. Which is the best option?
Last Answer : Here three different designing methods for 100 line exchange are discussed: Design 1: Here, Strowger switching system is designed using one two-motion selector for each subscriber. A ... only under certain specific traffic conditions and generally lead to higher blocking probabilities.
Description : How numbering plan is achieved in modern telephony? Give the structure with example.
Last Answer : The objective of numbering plan is to uniquely identify every subscriber connected to a telecommunication network. A numbering plan may be open, semiopen or closed. An open-numbering plan permits wide ... known as the subscriber number which is the number listed in the telephone directory.
Description : How does a touch tone receiver differs from pulsed dial receiver? Explain with schematic.
Last Answer : Pulse dialing: 1. Generated through make and break contact. 2. DC Current pulse is generated. 3. Each number is separated by a short pause to prevent overlapping. 4. Codes ... dialing pulse is not misinterpreted as the phone being returned to its on-hook (idle) condition.
Description : Discuss different Routing plan adopted in a Telephone network.
Last Answer : Hierarchical networks are capable of handing heavy traffic where required, and at the same time use minimal number of trunk groups. Three methods are used for deciding on the route for a ... selection methods can be implemented. Computer based routing is a standard feature in data networks.
Description : Discuss briefly subscriber loop system. Give some technical specification for subscriber lines.
Last Answer : Subscriber Loop System: Every subscriber in a telephone network is connected generally to the nearest switching office by means of a dedicated pair of wires. Subscriber loop refers to this pair of wires. It is un ... 1. Diameter of wire 2. D.C. resistance per Km 3. Attenuation per Km
Description : What is Traffic Engineering? Define the term busy hour, traffic intensity and grade of service.
Last Answer : Traffic engineering provides the basis for analysis and design of telecommunication network to carry a given traffic at a particular loss probability. It provides a means to determine the quantum of common equipments ... A0 Where A= offered traffic A0 = carried traffic A-A0= lost traffic
Description : Explain topology method used in LAN technology in detail.
Last Answer : LAN Topologies: Network topology is a physical schematic which shows interconnection of the many users. There are four basic topologies as under: (i) Direct Connection or one to all topology ( ... temporarily, inserting the new node and then reestablishing the complete ring path.
Description : List all seven layer of OSI model and describe function of application layer.
Last Answer : The layers of OSI model are as follows: (1) The Physical Layer: This defines an interface in terms of the connections, voltage levels and data rate, in order for signals to ... with the applications programs needed. Examples include electronic mail, word processing, banking transactions, etc.
Description : Find the total number of link L having five entities? Explain differences between folded and non-folded network.
Last Answer : Folded network: When all the inlets/outlets are connected to the subscriber lines, the logical connection appears as shown in Fig. In this case, the output lines are folded back to the input ... non-folded network to be non-blocking, the network should support N simultaneous switching paths.
Description : Explain simple telephone communication system with circuit and equation of current flow in microphone?
Last Answer : Simple Telephone Communication: In the simplest form of a telephone circuit, there is one way communication involving two entities, one receiving (listening) and the other transmitting (talking). ... carrier wave in AM system. The quantity m is equivalent to the modulation index in AM.
Description : Explain crossbar exchange, with all call processing steps and diagrams
Last Answer : The basic idea of crossbar switching is to provide a matrix of n x m sets of contacts with only n + m activators or less to select one of the n x m sets of contacts. This form of ... a contact is established at the cross point 6 such that the subscriber B is connected to the subscriber C.
Description : What are the advantages and disadvantages of packet switching over circuit switching?
Last Answer : The comparison of packet switching and circuit switching showing advantages and disadvantages of packet switching over circuit switching is given below:
Description : What are the advantages of CCS over in-channel signalling?
Last Answer : The advantages of CCS over in-channel signalling are listed below: a. Information can be exchange between the processors much more rapidly than when channel associated signaling is used. b ... for functions other than call processing, for example for maintenance or network management purposes.
Description : Explain the CCITT hierarchical structure of switching and routing using block schematic.
Last Answer : Hierarchical network are capable of handing heavy traffic where required, and at the same time use minimal number of trunk groups. A 5-level switching hierarchy is recommended by CCITT as ... A strictly hierarchical network suffers from serious drawback i.e. its poor fault tolerance future.
Description : Through two block diagrams explain the difference between Space division and time division switching.
Last Answer : Space and Time Switching: Space Switches: Connections can be made between incoming and outgoing PCM highways by means of a cross point matrix of the form shown in Fig. However, different channels of ... of the speech store, whose contents are read out and sent over the outgoing highway.
Description : Show how finite state machine model helps in designing a switching system and give a typical example.
Last Answer : Switching system basically belongs to the class of finite state machines (FSM) which are asynchronous in nature and follows a sequential logic for their operation. They can be modeled by ... circuits and memory elements. Clocked synchronous operation shown in Fig. overcome such problems.
Description : What are different control function categories, explain, how they help in signalling and control.
Last Answer : In some switching systems, the control subsystem may be an integral part of the switching network itself. Such system is known as direct control switching systems. Those systems in which the control ... may be carried out at the level of the common control unit or the switching network.
Description : Explain the architecture of SS7 and compare with seven-layer OSI architecture.
Last Answer : A block schematic diagram of the CCITT no. 7 signaling system is shown in fig. Signal messages are passed from the central processor of the sending exchange to the CCS system. This consists of the microprocessor based ... part (TUE), the data user part(DUP) and the (ISDN) user part (ISDN-UP).
Description : What is centralized SPC, what are its modes of operation; explain the working of any one of these?
Last Answer : In centralized control, all the control equipment is replaced by a single processor which must be quite powerful. It must be capable of processing 10 to 100 calls per second, depending on ... The shared secondary storage need not be duplicated and simple unit level redundancy would suffice.
Description : Compare electromechanical switching system with electronic switching system.
Last Answer : Ans:
Description : In a hundred-line exchange 24 two-motion selectors are used. Draw the schematic you suggest for this exchange and explain its working. How many simultaneous calls can be made during peak hour in this exchange?
Last Answer : The desired schematic for 100 lines exchange with 24 two motion selectors is shown in Fig. In the case, 24 simultaneous calls can be put through the switch . Typically, a 24- ... selector. At the next step, the two-motion selector responds to the dial pulses for appropriate connection.
Description : Explain the terms. (i) Register marker. (ii) Conditional selection.
Last Answer : (i) Register marker: Strowger selectors perform counting and searching. However, the crossbar switch has no intelligence'. Something external to the switch must decide which magnets to operate. This is ... are found to be free does it operate the switches. This is called Conditional Selection.