310203gA Intro To Data Communications - Part A

Question 1

What are the three data transmission modes?

Answer 1

1. Simplex - data transmission in one direction only
2. Half duplex - data transmission is possible in both directions but not at the same time
3. Full-duplex - data transmission is possible in both directions at the same time

Question 2

Define simplex mode data transmission

Answer 2

In simplex (SX) mode, data transmission is in one direction only

Question 3

Define half-duplex data transmission

Answer 3

In half-duplex (HDX) mode, data transmission is possible in both directions, but not at the same time

Question 4

Define full-duplex data transmission

Answer 4

In full-duplex (FDX) mode, data transmission is possible in both directions at the same time

Question 6

The speed at which serial communication happens is described in three different ways, what are they?

Answer 6

1. Bit rate - number bits transmitted per second
2. Characters per second - the number of characters transmitted per second
3. Baud rate - the number of symbols transmitted per second

Question 7

What are the five common network topologies?

Answer 7

1. Point-to-point
2. Star
3. Bus
4. Ring
5. Mesh

Question 8

What type of network topology is this?

Answer 8

A point-to-point network

Question 9

What type of network topology is this?

Answer 9

A star network

Question 10

What type of network topology is this?

Answer 10

A bus network

Question 11

What type of network topology is this?

Answer 11

A ring network

Question 12

What type of network topology is this?

Answer 12

A mesh network

Question 13

What are the three common data error detection methods?

Answer 13

1. Parity (vertical redundancy) checking
2. Checksum
3. Cyclic redundancy checking

Question 15

What is an RS-232 signal used for?

Answer 15

RS-232 is a common serial communication standard for point-to-point communications.

RS-232 networks are intended to connect only two devices and are mainly used to connect two computers together without modems

Question 16

Describe the transmission system used and the electrical characteristics of the RS-232 communication standard

Answer 16

The RS-232 standard uses an unbalanced or single-ended transmission system
Unbalanced transmission requires two wires to transmit data:
1. One wire carries the varying voltage (transmitted data)
2. The other wire provides a reference voltage, usually ground