Cisco 200-120 Pass4sure Questions

200-120 Question 4

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.


Correct Answer: A,D,E
Explanation/Reference:
The idea behind a WAN is to be able to connect two DTE networks together through a DCE network. The network's DCE device (inclu des CSU/DSU) provides clocking to the DTE- connected interface (the router's serial interface).

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 tw o digital lines - For more 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 d emarcation 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.