UGC NET COMPUTER SCIENCE MODEL QUESTION-ANSWERS

 1. Traffic Intensity can be measured in
(A) Erlangs                (B) CCS
(C) CM               (D) All of the above
Ans: (D)

2. Trunks are the lines that run between
(A) Subscribers and exchange
(B) Switching system and power plant
(C) Local area network
(D) Switching stations
Ans: (D)

3. The number of point to point links required in a fully connected network for 50

entities is

(A) 1250                 (B) 1225

(C) 2500                  (D) 50

Ans: (C)

4. For a non blocking cross bar configuration, taking N as the number of subscribers,

there will be ______number of cross points and _______number of switches for

establishing connections when all the subscribers are engaged.

(A) N/2, N2                     (B) N2 , N/2

(C) 2N, N2                      (D) N/2, N3

Ans: (B)

5. Echo suppressor is detrimental to full duplex operation because

(A) It disables one of the two pairs in a four-wire trunk line when a signal is

detected on the other pair.

(B) It enables one of the two pairs in a four-wire trunk line when a signal is

detected on the other pair.

(C) It activates both the pairs of a four-wire trunk line.

(D) It is independent of line conditions.

Ans: (A)

6. Telephone companies normally provide a voltage of __________to power

telephones.

(A) +24 volts DC                    (B) -24 volts DC

(C) +48 volts DC                    (D) -48 volts DC.

Ans: (D)

7. The situation when both transmitter and receiver have to work in tandem is referred

to as

(A) parallel                            (B) serial

(C) synchronous                     (D) asynchronous

Ans: (C)

8. 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.

 Ans: (C)

9. A large numbers of computers in a wide geographical area can be efficiently

connected using

(A) twisted pair lines                          (B) coaxial cables

(C) Communication satellites             (D) all of the above

Ans: (D)

 10. Which transmission mode is used for data communication along telephone lines?

(A) Parallel                 (B) Serial

(C) Synchronous        (D) Asynchronous

Ans: (B)

 11. A sample rate of ________is required for a good quality representation of telephone

conversation.

(A) 4500 times per second.

(B) 700 integer sample points per minute.

(C) 50 times per second per mile of distance travelled.

(D) 8000 times per second.

Ans: (C)

 12. The ________is a circuit-switched network, while the ______is a packet-switched

network.

(A) Telephone, ATM                     (B) SONET and FDDI

(C) Satellite, Telephone               (D) FDDI and SONET

Ans: (A)

13. A Master group consists of

(A) 12 voice channels.                  (B) 24 voice channels

(C) 60 voice channels.                  (D) 300 voice channels

Ans: (D)

14. Direct inward dialling is used as a feature in

(A) PSTN.                                     (B) PBX.

(C) EPABX.                                  (D) VPN.

Ans: (C)

15. Trunks are the lines that run between

(A) Subscribers and exchange

(B) switching system and power plant

(C) Local area network.

(D) Switching stations.

Ans: (D)