Telephony - Electronics Engineering test questions

Telephony - Electronics Engineering test questions

(1) In telegraph, let the duration of smallest code be 25 ms. The speed will be

(A) 25,000 bauds
(B) 25 bauds
(C) 40 bauds
(D) 50 bauds

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(2) The frequency of dial tone in telephones is

(A) 33 Hz
(B) 1 Hz
(C) 13 Hz
(D) 133 Hz

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(3) Two messages can be transmitted simultaneously in one direction by the circuit called
(A) Diplex
(B) Simplex
(C) Duplex
(D) None of the above

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(4) The ideal grade of services is

(A) 0 %
(B) 1 %
(C) 10 %
(D) 100 %

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(5) For the same capacity, the exchange that will occupy the least space is

(A) Cross bar exchange
(B) Process controlled exchange
(C) Strowger type exchange
(D) All will occupy the same space

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(6) The electrical power output in carbon microphone is

(A) More than the incident accaustic power
(B) Less than the incident accaustic power
(C) Equal to the incident accaustic power
(D) None of the above

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(7) In carrier system, frequency frogging is used to

(A) Reduce cross talk
(B) Reduce distortion
(C) Conserve frequencies
(D) None of the above

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(8) Which one of the following code is used in Bandot system?

(A) Morse
(B) ASCH
(C) Seven unit
(D) Five unit

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(9) What is Cross-talk?

(A) Distortion in demodulated signal
(B) Interference in the electromagnetic waves
(C) Distortion in adjacent telephone lines
(D) Distortion in adjacent telegraphy lines

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(10) How many pulses will be generated in7 ½ code?

(A) 10
(B) 1
(C) 15
(D) 8

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(11) The principle on which a bridge duplex works is

(A) Potential balance
(B) Power balance
(C) Current balance
(D) Resistance balance

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(12) Which one of the following statement is true for sub-group pilot?

(A) It is applied at each adjustable equalizer
(B) It is fed in at a GTE
(C) It is applied at each multiplexing bay
(D) It is used to regulate the gain of individual repeaters

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(13) Telephone traffic is measured in terms of

(A) Numbers
(B) Hz
(C) Bauds
(D) Erlangs

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(14) In a relay, a slug increases

(A) Both release lag and operate lag
(B) Operate lag
(C) Release lag
(D) None of the above

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(15) In a FDM receiver, in order to separate channels it is necessary to use

(A) Band pass filters
(B) AND gate
(C) Integration
(D) Differentiation

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(16) For telegraphy, the most common modulation system used is

(A) Frequency shift keying
(B) Two tone modulation
(C) Pulse code modulation
(D) Single tone modulation

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(17) The one, which is not, a binary code is

(A) CCITT-2
(B) ARQ
(C) Morse
(D) Baudot

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(18) The advantage of transposition on telephone lines is

(A) It reduces interference
(B) It reduces cross talk
(C) It reduces side tone
(D) All of the above

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(19) In order to maintain a cross point in a crossbar switch, the number of magnets, which are to remain, operated is

(A) Four
(B) Three
(C) Two
(D) One

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(20) Which one of the following statement is true for the ordinary telephone hand set?

(A) We usually use carbon microscope as transmitter
(B) We usually use dynamic microphone as transmitter
(C) We usually use crystal microphone
(D) None of the above

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(21) Full form of TELEX is

(A) Telegraph control room
(B) Telegraph exchange
(C) Telephone exchange
(D) Teleprinter exchange

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(22) Function of wipers in uniselector is

(A) Moving parts of establishing contacts with different bank contacts
(B) These are fixed points at which the contacts are made
(C) Parts of switch, which are generally fixed
(D) None of the above

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