INTGRATED SERVICES DIGITAL NETWORK (ISDN)

Question 1

What is PSTN?

Answer 1

Public Switched Telephone Network

Question 2

Traditional PSTN is analog or digital?

Answer 2

Analog

Question 3

Purpose of Modem?

Answer 3

To allow digital data to be transmitted using analog transmission systems

Question 4

What is the purpose of Integrated Services Digital Network (ISDN)?

Answer 4

ISDN provides an interface for devices so that we can send digital voice, video and data through preexisting analog PSTN

Question 5

What are the two Integrated Services Digital Network (ISDN) options?

Answer 5

Basic Rate Interface (BRI) and Primary Rate Interface (PRI)

Question 6

What are the channels used by Basic Rate Interface (BRI)?

Answer 6

2B + D
2 Bearer Channel
1 Data Channel

Question 7

What is a Bearer Channel?

Answer 7

Bears traffic from point to point

Question 8

Data rate of Bearer Channel?

Answer 8

64 Kbps

Question 9

What is a Data Channel?

Answer 9

Carries the information about the Data (e.g. initiating, terminating, etc.) and signaling data for control

Question 10

Data rate of Data Channel in Basic Rate Interface (BRI)?

Answer 10

16 Kbps

Question 11

Data rate of Data Channel in Primary Rate Interface (PRI)?

Answer 11

64 Kbps

Question 12

What are the channels used by Primary Rate Interface (PRI)?

Answer 12

23B + D
23 Bearer Channels
1 Data Channel

Question 13

What is the reason for ISDN’s decline?

Answer 13

Switch to Digital and IP-based technology. It declines because ISDN relies on analog medium like PSTN.

Question 14

Why was ISDN invented?

Answer 14

Because analog data is susceptible to noises, has limited bandwidth, and harder to manipulate (e.g. regenerate).