1. What signal-to-noise ratio is needed to put a T1 carrier on a T0-kHz line ?

63 db

73 db

83 db

93 db

2. If data rate of ring is 20 Mbps, signal propagation speed is 200 b/ms, then number of bits that can be placed on the channel of 200 km is

2000 bits

20,000 bits

1,000 bits

none of these

3. A field in the Ethernet message packet is

Type

data

address

none of these

4. Minimum number of bits required to represent all the symbols together is

15

14

12

11

5. Which of the following measures the number of lost or garbled messages as a fraction of the total sent in the sampling period ?

Residual error rate

Transfer failure probability

Connection release failure probability

Connection establishment failure probability

6. Maximum data rate of a channel for a noiseless 3-kHz binary channel is

3000 bps

1500 bps

6000 bps

none of these

7. Number of cross point needed for 10 lines in a cross point switch which is full duplex in nature and there are no self-connection is

100

45

8

. 28

8. The systems that can be used in both priority and non-priority modes is

TDM

Register insertion

Carrier sense systems

all of these

9. In the carrier sense network, if prevailing condition is a 'channel busy', then technique used is

non-persistent then it results in randomised wait and sense

1-persistent then the channel is continually sensed

p-persistent then randomised retransmission is done

both (a) and (b)

10. Start and stop bits are used in serial communication for

error detection

error correction

synchronization

slowing down the communication