MSIS 605 exercise 3
Exercises –Chapter 3
Chapter 3- Physical Layer
1
Q1
• How does a multipoint circuit differ from a point-to-point circuit? • A point-to-point configuration is so named because it goes from one point to another (e.g., one computer to another computer). These circuits sometimes are called dedicated circuits because they are dedicated to the use of these two computers. • In a multipoint configuration (also called a shared circuit), many computers are connected on the same circuit. This means that each must share the circuit with the others, much like a party line in telephone communications. The disadvantage is that only one computer can use the circuit at a time. Multipoint configurations are cheaper than point-to-point configurations.
Chapter 3- Physical Layer
2
Q2
• Describe the three types of data flows.
• The three types of data flows are simplex, half-duplex and full duplex.
• Simplex is one-way transmission, such as that in radio or TV transmission.
• Half duplex is two-way transmission, but you can transmit in only one direction at a time. A half duplex communication link is similar to a walkie-talkie link; only one computer can transmit at a time.
• With full duplex transmission, you can transmit in both directions simultaneously, with no turnaround time.
Chapter 3- Physical Layer
3
Q3
• Explain why most telephone company circuits are now digital.
• Digital transmission produces fewer errors than analog transmission. Because the transmitted data is binary (only two distinct values), it is easier to detect and correct errors.
• Digital transmission is more efficient. Time division multiplexing
(TDM) is more efficient than frequency division multiplexing (FDM) because TDM requires no guardbands. TDM is commonly used for digital transmission, while FDM is used for analog transmission.
• Digital transmission permits higher maximum transmission rates.
Fiber optic cable, for example, is designed for
Chapter 3- Physical Layer
1
Q1
• How does a multipoint circuit differ from a point-to-point circuit? • A point-to-point configuration is so named because it goes from one point to another (e.g., one computer to another computer). These circuits sometimes are called dedicated circuits because they are dedicated to the use of these two computers. • In a multipoint configuration (also called a shared circuit), many computers are connected on the same circuit. This means that each must share the circuit with the others, much like a party line in telephone communications. The disadvantage is that only one computer can use the circuit at a time. Multipoint configurations are cheaper than point-to-point configurations.
Chapter 3- Physical Layer
2
Q2
• Describe the three types of data flows.
• The three types of data flows are simplex, half-duplex and full duplex.
• Simplex is one-way transmission, such as that in radio or TV transmission.
• Half duplex is two-way transmission, but you can transmit in only one direction at a time. A half duplex communication link is similar to a walkie-talkie link; only one computer can transmit at a time.
• With full duplex transmission, you can transmit in both directions simultaneously, with no turnaround time.
Chapter 3- Physical Layer
3
Q3
• Explain why most telephone company circuits are now digital.
• Digital transmission produces fewer errors than analog transmission. Because the transmitted data is binary (only two distinct values), it is easier to detect and correct errors.
• Digital transmission is more efficient. Time division multiplexing
(TDM) is more efficient than frequency division multiplexing (FDM) because TDM requires no guardbands. TDM is commonly used for digital transmission, while FDM is used for analog transmission.
• Digital transmission permits higher maximum transmission rates.
Fiber optic cable, for example, is designed for