WGU D413 – Telecommunications &
Wireless Communications Objective
Assessment | OA V1 and V2 | Questions
and Answers | 2026 Update | 100%
Correct.
VERSION 1 (V1)
Question 1
Which component converts digital signals into analog signals for transmission
over traditional phone lines?
A) Router
B) Switch
C) Modem
D) Repeater
Correct Answer: C
Rationale: A modem (modulator-demodulator) converts digital data from computers into
analog signals for transmission over traditional telephone lines and demodulates analog
,signals back into digital data at the receiving end. This conversion is necessary because
standard phone lines were originally designed for analog voice transmission .
Question 2
Which transmission medium provides the highest bandwidth and immunity to
electromagnetic interference (EMI)?
A) Twisted pair copper
B) Coaxial cable
C) Fiber-optic cable
D) Microwave
Correct Answer: C
Rationale: Fiber-optic cables transmit data as pulses of light rather than electrical signals,
making them immune to electromagnetic interference (EMI) and radio frequency
interference (RFI). They offer extremely high bandwidth, low signal loss, and high security
against tapping .
Question 3
What is the primary purpose of multiplexing in telecommunications?
A) Error correction
B) Combining multiple signals into one channel
C) Increasing signal strength
D) Encrypting data
Correct Answer: B
Rationale: Multiplexing allows multiple data streams to share a single transmission
medium, improving efficiency. It is a fundamental technique for maximizing the use of
available bandwidth .
,Question 4
Which layer of the OSI model is responsible for end-to-end flow control, error
detection, and reliable data delivery?
A) Network Layer
B) Data Link Layer
C) Transport Layer
D) Session Layer
Correct Answer: C
Rationale: The Transport Layer (Layer 4) manages end-to-end communication control,
ensuring packets arrive error-free, in sequence, and without loss using protocols like TCP.
It provides flow control, error checking, and segmentation of data .
Question 5
What is the purpose of a subnet mask in IP networking?
A) Encrypt data
B) Define which portion of an IP address is the network and which is the host
C) Assign MAC addresses
D) Monitor network traffic
Correct Answer: B
Rationale: Subnet masks divide an IP address into network and host portions, allowing
proper routing and subnetting. For example, a subnet mask of 255.255.255.0 indicates
that the first three octets are the network portion and the last octet is the host portion .
Question 6
, Which protocol is primarily used for secure file transfer over a network?
A) FTP
B) Telnet
C) SFTP
D) HTTP
Correct Answer: C
Rationale: SFTP (Secure File Transfer Protocol) encrypts both commands and data, unlike
FTP which transmits data in plaintext. It provides secure file transfer capabilities over SSH .
Question 7
Which device separates collision domains but not broadcast domains?
A) Router
B) Hub
C) Switch
D) Repeater
Correct Answer: C
Rationale: Switches create separate collision domains per port but all ports remain in the
same broadcast domain unless VLANs are configured. This improves network efficiency by
reducing collisions .
Question 8
What does latency measure in a telecommunications network?
A) The amount of data that can be transmitted per second
B) The time it takes for a packet to travel from source to destination
C) The variation in packet arrival times
D) The percentage of packets lost during transmission
Wireless Communications Objective
Assessment | OA V1 and V2 | Questions
and Answers | 2026 Update | 100%
Correct.
VERSION 1 (V1)
Question 1
Which component converts digital signals into analog signals for transmission
over traditional phone lines?
A) Router
B) Switch
C) Modem
D) Repeater
Correct Answer: C
Rationale: A modem (modulator-demodulator) converts digital data from computers into
analog signals for transmission over traditional telephone lines and demodulates analog
,signals back into digital data at the receiving end. This conversion is necessary because
standard phone lines were originally designed for analog voice transmission .
Question 2
Which transmission medium provides the highest bandwidth and immunity to
electromagnetic interference (EMI)?
A) Twisted pair copper
B) Coaxial cable
C) Fiber-optic cable
D) Microwave
Correct Answer: C
Rationale: Fiber-optic cables transmit data as pulses of light rather than electrical signals,
making them immune to electromagnetic interference (EMI) and radio frequency
interference (RFI). They offer extremely high bandwidth, low signal loss, and high security
against tapping .
Question 3
What is the primary purpose of multiplexing in telecommunications?
A) Error correction
B) Combining multiple signals into one channel
C) Increasing signal strength
D) Encrypting data
Correct Answer: B
Rationale: Multiplexing allows multiple data streams to share a single transmission
medium, improving efficiency. It is a fundamental technique for maximizing the use of
available bandwidth .
,Question 4
Which layer of the OSI model is responsible for end-to-end flow control, error
detection, and reliable data delivery?
A) Network Layer
B) Data Link Layer
C) Transport Layer
D) Session Layer
Correct Answer: C
Rationale: The Transport Layer (Layer 4) manages end-to-end communication control,
ensuring packets arrive error-free, in sequence, and without loss using protocols like TCP.
It provides flow control, error checking, and segmentation of data .
Question 5
What is the purpose of a subnet mask in IP networking?
A) Encrypt data
B) Define which portion of an IP address is the network and which is the host
C) Assign MAC addresses
D) Monitor network traffic
Correct Answer: B
Rationale: Subnet masks divide an IP address into network and host portions, allowing
proper routing and subnetting. For example, a subnet mask of 255.255.255.0 indicates
that the first three octets are the network portion and the last octet is the host portion .
Question 6
, Which protocol is primarily used for secure file transfer over a network?
A) FTP
B) Telnet
C) SFTP
D) HTTP
Correct Answer: C
Rationale: SFTP (Secure File Transfer Protocol) encrypts both commands and data, unlike
FTP which transmits data in plaintext. It provides secure file transfer capabilities over SSH .
Question 7
Which device separates collision domains but not broadcast domains?
A) Router
B) Hub
C) Switch
D) Repeater
Correct Answer: C
Rationale: Switches create separate collision domains per port but all ports remain in the
same broadcast domain unless VLANs are configured. This improves network efficiency by
reducing collisions .
Question 8
What does latency measure in a telecommunications network?
A) The amount of data that can be transmitted per second
B) The time it takes for a packet to travel from source to destination
C) The variation in packet arrival times
D) The percentage of packets lost during transmission
