Pine Bluff Cable Television : High Speed Internet - Understanding Modem Technology

HIGH SPEED INTERNET SERVICES: UNDERSTANDING CABLE MODEM TECHNOLOGY

What is a cable modem?
A cable modem is a device that connects your computer to the Internet via your local cable television provider. A cable modem has two connections, one that leads to the cable lines outside your home and one that connects connects to your computer, typically via an Ethernet connection. A one-way cable modem will also have a telephone line connection.

How does a cable modem work?
Cable modems modulate and demodulate RF signals. The cable modem receives data in what is known as the downstream signal. This signal is modulated on television channels that are six MHz wide at frequencies between 88 to 750 MHz. This signal usually runs adjacent to other television signals.

How does a cable modem connect to a computer?
There are typically three main components that connect a cable modem to a computer: a coaxial cable, a Category 5 twisted pair line, and, a 10Base-T Ethernet network interface card (also called a NIC card) or a USB Ethernet Port. The coaxial cable line from the outside of the building connects to the cable modem. The Category 5 twisted pair line connects the computer to the cable modem. The network interface card inside the computer enables the cable modem to "talk" to the computer.

Can I watch television and browse the Internet at the same time?
Yes. Since television and the cable modem operate on separate frequencies of the available cable bandwidth, you will be able to watch television and browse the Internet at the same time.

How fast will a cable modem download and upload data?
Cable modem speeds vary depending on network architecture and configuration, local bandwidth provisioning, your system configuration, the number of users accessing the network at the same time, and the service level to which you subscribe.

The asymmetric cable modem scheme is the most common type of cable network setup, and will allow for a faster data transmission rate (higher bandwidth) on the downstream data path than the upstream data path. This network setup works well since most cable modem users download more information than they send. For example, downloading web pages and multimedia files and participating in newsgroups requires much more bandwidth than sending web page requests or email.

Is a telephone line still required when using a cable modem to access the Internet?
No. You will not need a telephone line when using a two-way cable modem. The cable line carries both upstream and downstream signals.

How does a cable modem compare to a dialup modem?
Cable modems can connect to the Internet and download information much faster than a dialup modem. For example, it will take a cable modem user milliseconds to connect to the Internet while it will take a dialup modem user about a minute. Cable modems can also download information at speeds up to 512 Kbps while a dialup modem will only download information at 53 Kbps or less.