Post subject: WAN question Posted: Thu Nov 18, 2010 10:47 am
Help others: Review your books and training products here
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.
I want to see what the answer is, I don't understand the modem and the csu/dsu part. _________________ FJohnson
A+, Network+, MCSE 2000.
soon CCNA.
Help others: Review your books and training products here
The answer is A, D, E.
A: A CSU/DSU terminates a digital local loop.
A CSU/DSU is used for example to connect a customer to a T1 line (digital line). They can look like a modem or be built into a WAN card in a router. The DTE device (usually a router) connects to the CSU/DSU. So a CSU/DSU terminates a digital line.
D. A modem terminates an analog local loop.
An example of this is a dial up connection. The modem converts data to an acceptable form to go over the phone line (analog). The modem terminates the analog line. _________________ A+
Net+
CCENT
CCNA
Help others: Review your books and training products here
I guess that "D" is the one I don't understand. In my studies it says that "A Modem converts digital signal to Analog, Then back again". _________________ FJohnson
A+, Network+, MCSE 2000.
soon CCNA.
Help others: Review your books and training products here
Ok, think of it this way.
---Computer -- Switch -- Modem -- Analog line
--- digital --- digital -- digital - analog -- analog
When traffic is coming back from the internet it is in analog form when it's going over the analog line, when it gets to the modem the modem will convert it back to digital.
So a modem does "converts digital signal to Analog, Then back again. BUT at the same time it's the termination of the analog local loop. _________________ A+
Net+
CCENT
CCNA
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum
