Which of the following describes the roles of devices in a WAN? (Choose three.)

A. A CSU/DSU terminates a digital local loop.

B. A modem terminates a digital local loop.

C. A CSU/DSU terminates an analog local loop.

D. A modem terminates an analog local loop.

E. A router is commonly considered a DTE device.

F. A router is commonly considered a DCE device.




 

Suggested Answer: ADE

The idea behind a WAN is to be able to connect two DTE networks together through a DCE network. The network's DCE device (includes CSU/DSU) provides clocking to the DTE-connected interface (the router's serial interface).
 <img src="https://www.examtopics.com/assets/media/exam-media/01508/n43898700001.png" alt="Reference Image" />
A modem modulates outgoing digital signals from a computer or other digital device to analog signals for a conventional copper twisted pair telephone line and demodulates the incoming analog signal and converts it to a digital signal for the digital device. A CSU/DSU is used between two digital lines -
For more explanation of answer D, in telephony the local loop (also referred to as a subscriber line) is the physical link or circuit that connects from the demarcation point of the customer premises to the edge of the carrier or telecommunications service provider's network. Therefore, a modem terminates an analog local loop is correct.
 <img src="https://www.examtopics.com/assets/media/exam-media/01508/n43898700000.jpg" alt="Reference Image" />

This question is in CCNA 200-125 exam 
For getting CCNA Certificate


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