How Cable Modems Work


How Cable Modems Work

The coaxial cablesometimes called a broadband wirethat comes into a home from a pole is divided into two connections by a splitter inside the home. One part of the wire goes to the normal set-top box that provides cable TV access. The other part of the wire goes to a cable modem, sometimes called a broadband modem.



 


How Internet-Enhanced TV Works

To receive Internet-enhanced TV, a television set requires a special set-top box that can receive and deliver the Internet-enhanced services. The set-top box has a powerful processor and a hard disk inside it.



 


How IPTV Works

Video signals are received by the telephone company's national head end, which pulls in video feeds from satellites.



 


Chapter 9. How Wireless Connections and WiFI Work

The wired world created a revolution of allowing people to connect to the Internet. Now the unwired worldthe ability to connect to the Internet wirelesslyis bringing just as big a change.

The most popular way of connecting to the Internet wirelessly is via a family of technologies called 802.11 or WiFi. There are several different standards for 802.11, and they connect at different speeds, including 802.11b standard, which operates in the 2.4GHz spectrum and transfers data at a maximum rate of 11Mbps; the 802.11a standard, which operates in the 5GHz spectrum at 54Mbps; and the 802.11g standard, which operates in the 2.4GHz spectrum and transfers data at a maximum rate of 54Mbps. In addition, there are other emerging standards that transfer data at much higher rates, such as the 802.11n, which will transfer data at rates approximately ten times faster than 802.11g.

To connect to the Internet this way, an 802.11 card needs to be used in a computing device such as a laptop or palmtop computer, and it needs to connect to a nearby compatible wireless access point, most often called a router. These routers can be in a home or business. Increasingly there are also public access points, called hot spots, which allow you to connect to the Internet from public places such as coffee shops, hotels, and airports.

One problem with WiFi networks is that they can be vulnerable to snoopers and hackers, who can use a technique called war driving to get into the network.

There are a variety of other ways to connect wirelessly to the Internet as well, for example by using a satellite connection.

Satellite-access systems are, in a way, odd hybrids. Many, but not all, still require that you use a modem. The modem is used to request information from the Internet, so when you send information through the Internet, it goes at normal modem speeds. However, that requested information is sent back to you at the high satellite transmission speeds, not the slower modem speeds. However, this means that if you're sending email, or transferring a file to someone via FTP, that information is sent at modem speeds, not satellite speeds.

When you access the Internet via satellite, you still use a traditional PC. However, you can also get onto the Web in other ways using new types of digital devices, most notably palmtop devices. These little computers, sometimes called personal digital assistants (PDAs) can literally put the Web in the palm of your hand. You connect a modem to them and can then get onto the Internet and send and receive email and browse the Web with them, although as explained earlier, you can also use them to access the Internet using WiFi technology.

An emerging technology may be the most revolutionary wireless technology of allWiMax blankets an entire metropolitan area with high-speed Internet access, and so wherever you are, you can be connected to the Internet.