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# MCQ in Wire and Wireless Communications System Part 4 | ECE Board

This is the Multiples Choice Questions Part 4 of the Series in Wire and Wireless Communications System as one of the Communications Engineering topic. In Preparation for the ECE Board Exam make sure to expose yourself and familiarize in each and every questions compiled here taken from various sources including but not limited to past Board Examination Questions in Electronic System and Technologies, Communications Books, Journals and other Communications References.

#### MCQ Topic Outline included in ECE Board Exam Syllabi

• MCQ in Mobile Communications
• MCQ in Cellular Communication
• MCQ in Radio Paging System
• MCQ in Facsimile
• MCQ in Telephone Set
• MCQ in Signaling
• MCQ in Transmission Considerations in long distance network
• MCQ in Insertion Loss
• MCQ in VF Repeaters
• MCQ in Traffic Calculations
• MCQ in Reference Equivalent and Standards
• MCQ in Telephone Networks
• MCQ in Billing
• MCQ in Network Hierarchy and Class type
• MCQ in Connection and Performance of Wire and Wireless Communications

#### Continue Practice Exam Test Questions Part 4 of the Series

151. The telephone was invented by

a. Watson

b. Bell

c. Strowger

d. Edison

Solution:

152. The central office detects a request for service from a telephone by

a. A flow of loop current

b. No loop current

c. A ringing signal

d. Dial pulses

Solution:

153. Which office local is the local central office?

a. 2

b. 3

c. 4

d. 5

Solution:

154. Which exchange is used to connect between central offices when a direct trunk is not available?

a. Local

b. Tandem

c. Toll

d. Any of the above

Solution:

155. Which of the following is a type of dc signaling?

a. Loop current

b. Reverse battery

c. E and M

d. All of the above

Solution:

156. The voice frequency channel pass band is

a. 0 to 4000 Hz

b. 300 to 3000 Hz

c. 8140 to 8188 Hz

d. None of the above

Solution:

157. What is used to transmit more than one conversation over a path?

a. Hybrid

b. Tandem

c. Multiplexing

d. All of the above

Solution:

158. The common channel signaling method

a. Uses the same channel for signaling as for the related conversation

b. Uses a separate channel for signaling only

c. Carries the signaling for only one related conversation

d. Is used on local loops

Solution:

159. Telephone switching is accomplished by

a. Manual switchboard

b. Step-by-step switches

c. Crossbar switches

d. Any of the above

Solution:

160. The step-by-step switch

a. Was invented by Strowger

b. Generates much noise

c. Cannot operate directly from DTMF tones

d. All of the above

Solution:

161. Time division multiplexing is used for

a. Analog transmission

b. Digital transmission

c. Both of the above

d. None of the above

Solution:

162. What type of transmitter is most commonly used in a conventional telephone handset?

a. Carbon

b. Electromagnetic

c. Electret

d. Ceramic

Solution:

163. Which component in the telephone set has the primary function of compensating for the local loop length?

a. Resistor

b. Varistor

c. Capacitor

d. Induction coil

Solution:

164. What type of receiver is most commonly used in a conventional telephone handset?

a. Carbon

b. Electromagnetic

c. Electret

d. Ceramic

Solution:

165. Which component in the telephone set has the primary function of interfacing the handset to the local loop?

a. Resistor

b. Varistor

c. Capacitor

d. Induction coil

Solution:

166. How many unique tones are used for the 12-key dual-tone multi-frequency keypad?

a. 2

b. 3

c. 7

d. 12

Solution:

167. Which of the following are important for the proper interface of a DTMF generator to the telephone line?

a. Impedance

b. Tone amplitude

c. Loop current

d. All of the above

Solution:

168. The anti-tinkle circuit

a. Prevents tampering with the telephone

b. Prevents dial pulsing from ringing the bell

c. Prevents speech signals from ringing the bell

d. All of the above

Solution:

169. The sidetone is

a. A type of feedback

b. Determined by the balancing network

c. Permits the talker to hear his/her own voice

d. All of the above

Solution:

170. On-hook current must be kept low so that the

a. Line relays in the central office will not mistake it for off-hook current

b. Comparatively small wires in the cables will not overheat

c. Ringer will not ring incorrectly

d. Carbon microphone will not be damaged

Solution:

171. Overvoltage protection is

a. Needed in the telephone set because of the high ringing voltage

b. Is nearly always incorporated in the IC chip

c. Is primarily a central office function

d. Needed because of transients from dial pulsing, lightning, induction or short circuit

Solution:

172. A special rectifier bridge is used in electronic telephone because

a. The ac power must be converted to dc to simulate a battery

b. it is necessary to shunt the speech frequencies and keep them off of the loop

c. the voltage drop across conventional bridges leaves too little voltage to operate the set

d. All of the above

Solution:

173. Voltage and current regulation

a. Is provided by the central office

b. Is needed to ensure proper IC operation

c. Can be performed by circuits built into the IC

d. B and C above

Solution:

174. Memory is added to the telephone set to

a. Allow more digits to be dialed

b. Allow faster dialing

c. Allow automatic redialing of the last number dialed

d. None of the above

Solution:

175. What is the function of the diode rectifier bridge in the line circuit?

a. Lower the voltage to the telephone electronics

b. Raise the voltage to the telephone electronics

c. Short out the line when the set is on-hook

d. Protect the set against polarity reversals on the line

Solution:

176. What bad electrical effect happens when the switch-hook is opened?

a. A high voltage transient is generated

b. The line is shorted out

c. The line is opened

Solution:

177. Pulse dialing occurs at the rate of

a. 20 pulses per minute

b. 10 pulses per minute

c. 10 pulses per second

d. 80 pulses per second

Solution:

178. How many different tones may be produced by a four-column DTMF keypad?

a. 2

b. 8

c. 4

d. 16

Solution:

179. What is the advantage of electronic ringers?

a. Louder volume

b. Smaller size

c. Good directionality

d. Greater weight

Solution:

180. What function are provided in a multi-tone ringing generator?

a. Anti-tinkle circuitry

b. Tone generation

c. Output amplifier

d. All of the above

Solution:

181. The DTMF generator in an electronic phone produces tones using a(an)

a. LC circuit

b. RC circuit

c. Digital divider circuit

d. Digital multiplier circuit

Solution:

182. Which function is not required in an integrated telephone circuit?

a. Regulator

b. Dialer

c. Visual display

d. Speech network

Solution:

183. Transient protection is provided for integrated telephone circuits is typically provided by

a. Bridge rectifiers

b. Zener diodes

c. Inductors

d. Capacitors

Solution:

184. Speakerphones operate in

a. Full-duplex mode

b. Half-duplex mode

c. Open-duplex mode

d. Computer mode

Solution:

185. Sampling the analog wave produces

a. Impulse noise

b. Phase distortion

c. Pulse amplitude modulation

d. Frequency coherence

Solution:

186. The simplest form of coding is

a. Diphase

b. Hybrid

c. Compressed

d. Linear

Solution:

187. In digital multiplexing systems, bit interleaving is used in

a. Lower level systems

b. Higher level systems

c. To interleave a code word

d. All of the above

Solution:

188. Synchronous multiplexed systems have the time placement of bits

a. Dedicated

b. Unassigned

c. Random

d. As required

Solution:

189. A synchronous multiplexed systems are used

a. Mostly for voice transmission

b. Mostly for data transmission

c. To carry only speech information

d. All of the above

Solution:

190. Fold-over distortion or aliasing is

a. Eliminated by filtering out the frequencies below 300 Hz

b. Another name for crosstalk

c. The presence of spurious frequencies caused by having too high frequencies in the sampled signal

d. None of the above

Solution:

191. Multiplexer systems used in the public network are of the ______ type.

a. Synchronous

b. Plesiochronous

c. Asynchronous

d. Isochronous

Solution:

192. The line coding scheme used for the DS-1 signal is

a. Non-return-to-zero

b. Binary 3 zero-substitutions

c. Ternary

d. Bipolar

Solution:

193. Modems are required to connect to telephone lines because

a. The telephone network bandwidth is too high

b. The telephone network will not pass direct current

c. Telephone company rules require them

d. None of the above

Solution:

194. The most common technique for binary data transmission

a. Bisynchronous transmission

b. Synchronous transmission

c. Asynchronous transmission

d. Plesiochronous transmission

Solution:

195. Asynchronous data transmission requires a clock

a. At the transmitter end

c. At neither end

d. At both ends

Solution:

196. What kind of modulation is used in modems?

a. Phase modulation

b. Frequency modulation

c. Amplitude modulation

d. All of the above

Solution:

197. The parameter that most affects transmission of the high speed modem data is

a. Phase distortion

b. Amplitude distortion

c. Frequency shift

d. Impulse noise

Solution:

198. Protocols may be

a. Bit oriented

b. Byte oriented

c. Character oriented

a. All of the above

Solution:

199. The telephone network is being converted to digital operation primarily to

a. Carry digital computer data

b. Reduce costs

c. Improve speech quality

d. Increase system capacity

Solution:

200. A code for a 64-interval must produce how many bits?

a. 2

b. 10

c. 8

d. 7

Solution:

#### Questions and Answers in Wire and Wireless Communications System Series

Following is the list of multiple choice questions in this brand new series:

MCQ in Wire and Wireless Communications
PART 1: MCQ from Number 1 โ 50                                 Answer key: PART 1
PART 2: MCQ from Number 51 โ 100                            Answer key: PART 2
PART 3: MCQ from Number 101 โ 150                          Answer key: PART 3
PART 4: MCQ from Number 151 โ 200                          Answer key: PART 4
PART 5: MCQ from Number 201 โ 250                          Answer key: PART 5
PART 6: MCQ from Number 251 โ 300                          Answer key: PART 6
PART 7: MCQ from Number 301 โ 350                          Answer key: PART 7
PART 8: MCQ from Number 351 โ 400                          Answer key: PART 8
PART 9: MCQ from Number 401 โ 450                          Answer key: PART 9
PART 10: MCQ from Number 451 โ 500                        Answer key: PART 10

### Complete List of MCQ in Communications Engineering per topic

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