How Does Adsl Compare To Cable Modems; What Is The Expected Throughput; What Is The Microfilter Used For - ZyXEL Communications P-630-S Series Support Notes

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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?

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.

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.

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

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