A "Cable Modem" is a device that allows high speed data access (such as to the Internet) via a cable TV (CATV) network. A cable modem will typically have two connections, one to the cable wall outlet and the other to a computer (PC).
How Fast is Fast
On-line access via cable modems will soon allow PC users to download information from on-line services at a speed - 1,000 times faster than today's fastest telephone modems. In just 1.2 seconds, a user can download data that today takes 20 minutes to transfer via phone manufacturers' products. Compare cable modems with a typical 14.4 modem. Cable modem speeds range from 500Kbps to 10Mbps. So if your modem operates at about 14,000 bits per second, the slowest (first generation) cable modems operate up to 500,000 bits per second (for a difference of 486,000 bits per second). Hardware companies are presently developing 30Mbps cable modems (30,000,000 bits per second), which are thousands of times faster than 14.4 telephone modems.
Transfer Rate for a 10-Megabyte File
| Modem Speed / Type | Transfer Time |
|---|---|
| 9.6-Kbps Telephone Modem | 2.3 hours |
| 14.4-Kbps Telephone Modem | 1.5 hours |
| 28.8-Kbps Telephone Modem | 46 minutes |
| 56-Kbps Telephone Modem | 24 minutes |
| 128-Kbps ISDN Modem | 10 minutes |
| 1.54-Mbps T-1 Connection | 52 seconds |
| 4-Mbps Cable Modem | 20 seconds |
| 10-Mbps Cable Modem | 8 seconds |
How Does it Connect?
There are several methods for computer connection, but it appears that Ethernet 10BaseT is emerging as the most predominant method. Although it probably would be cheaper to produce the cable modem as an internal card for the computer, this would require different printed-circuit cards for different kinds of computers, and additionally would make the demarcation between cable network and the subscriber's computer too fuzzy.
Click Here [ http://www.cablemodems.com/work.html ] for more detailed information about how cable modems work.
What will it do?
The most popular service will undoubtedly be high speed Internet access. This will enable the typical array of Internet services at speeds of 100 to 1000 times as fast as a telephone modem. Other services may include access to streaming audio and video servers, local content (community information and services), access to CD-ROM servers, and a wide variety of other service offerings. New service ideas are being born daily.
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