ZyXEL Communications P-630-S Series Manual

P-630-S Series
Support Notes
Version 1.0
May/2005
ADSL FAQ
1. How does ADSL compare to cable modems?
2. What is the expected throughput?
3. What is the microfilter used for?
4. How do I know the ADSL line is up?
5. Does the VC-based multiplexing perform better than the LLC-based
multiplexing?
6. What are the signaling pins of the ADSL connector?

Configuration and Troubleshooting
1. How do I configure the Prestige?
2. How can I make the ADSL status icon show in the taskbar?
3. What shall I do if my connection parameter is not in the installed profiles?
4. What shall I do when the ADSL LED is off and I lost my internet access?
5. How can I do packet trace with the Prestige?
1. How does ADSL compare to Cable modems?
ADSL provides a dedicated service over a single telephone line; cable modems offer a
dedicated service over a shared media. While cable modems have greater downstream
bandwidth capabilities (up to 30 Mbps), that bandwidth is shared among all users on a
line, and will therefore vary, perhaps dramatically, as more users in a neighborhood
get online at the same time. Cable modem upstream traffic will in many cases be
slower than ADSL, either because the particular cable modem is inherently slower, or
because of rate reductions caused by contention for upstream bandwidth slots. The big
difference between ADSL and cable modems, however, is the number of lines
available to each. There are no more than 12 million homes passed today that can
support two-way cable modem transmissions, and while the figure also grows steadily,
it will not catch up with telephone lines for many years. Additionally, many of the
older cable networks are not capable of offering a return channel; consequently, such
networks will need significant upgrading before they can offer high bandwidth
services.
2. What is the expected throughput?
In our test, we can get about 1.6Mbps data rate on 15Kft using the 26AWG
loop. The shorter the loop, the better the throughput.
3. What is the microfilter used for?
Generally, the voice band uses the lower frequency ranging from 0 to 4KHz, while
ADSL data transmission uses the higher frequency. The microfilter acts as a low-pass
filter for your telephone set to ensure that ADSL transmissions do not interfere with

your voice transmissions. For the details about how to connect the microfilter please
refer to the user's manual.
4. How do I know the ADSL line is up?
You can see the DSL LED on the P-630-S is keeping on when the ADSL physical
layer is up.
5. Does the VC-based multiplexing perform better than
the LLC-based multiplexing?
Though the LLC-based multiplexing can carry multiple protocols over a single VC, it
requires extra header information to identify the protocol being carried on the virtual
circuit (VC). The VC-based multiplexing needs a separate VC for carrying each
protocol but it does not need the extra headers. Therefore, the VC-based multiplexing
is more efficient.
6. What are the signaling pins of the ADSL connector?
The signaling pins on the P-630-S's ADSL connector are pin 3 and pin 4. The middle
two pins for a RJ11 cable.
Configuration and Troubleshooting
1. How do I configure the Prestige?
(1). via the control panel of the utility

(2). via Device manager of Windows OS.
2. How can I make the ADSL status icon show in the
taskbar?
Click the ADSL icon in Control panel, the GUI below will show up.

And then click the first option to display the ADSL status icon in the taskbar.
3. What shall I do if my connection parameter is not in
the installed profiles?

You can use Windows’s Device Manager to configure your connection
parameters. Your ISP will tell you the parameters.
4. What shall I do when the ADSL LED is off and I lost
my internet access?

Please check the physical DSL line; it may be not well connected to the
modem.
5. How can I do packet trace with the Prestige?
(1). Click the Event tracer
(2). Then the Event Tracer will record all the traffic through the modem,
press the Refresh button, and you will get the updated packet trace. And
you can also save the captured packets.