Connection Technologies
| Not long ago, you had one choice to make for your Internet connection: which brand of modem to buy. Now, options abound, and you can choose among several technologies, speeds, and types of Internet service providers. A huge technology shift is taking place, as high-speed digital (broadband) connection services are being deployed worldwide. Let's take a look at the basic Internet connection technologies appropriate for an individual user or workgroup. After describing each one, I'll show you roughly what they cost to set up and use. Analog ModemStandard, tried-and-true dial-up modem service requires only a telephone line and a modem in your computer. The connection is made when your computer dials a local access number provided by your Internet service provider (ISP). The downside is that this ties up a telephone line while you're online. Furthermore, if you have call waiting, the "beep" that occurs when someone calls while you're online can make the modem drop its connection. To avoid these hassles, many people order an additional line just for the modem, and this adds to the monthly expense. NOTE Some modems and ISPs provide a service called Internet Call Waiting. The modem detects the call-waiting beep and notifies you via a pop-up window that a call is coming in; you can ignore it or suspend your Internet connection for a time while you take the call. This requires a modem supporting the V.92 standard and a participating ISP. The service costs upward of $8 per month, if it's even available, so it's not a big win as far as I can see. Modems transmit data at a top speed of 33Kbps and can receive data at up to 56Kbps (56 thousand bits per second). In real life, you will usually obtain download speeds of 40 to 50Kbps. This speed is adequate for general Web surfingthat is, reading text and viewing pictures. However, you will find it woefully inadequate for viewing video or for voice communication. To use standard dial-up service, you'll need a modem and a telephone cable. Modems come in internal, external, USB, and PC-Card varieties from dozens of manufacturers. Most computers made for home use come with one pre-installed. On business computers, they're usually an extra-cost item. ISDNIntegrated Services Digital Network (ISDN) is a special digital-only telephone service that can carry two independent voice or data conversations over one telephone wire. ISDN service is actually a different type of telephony; you can't plug ordinary telephones into an ISDN line. ISDN modems can carry data at 64 or 128Kbps, depending on whether you use one or two of its channels to connect to your ISP. Thanks to the worldwide spread of cable and DSL service, ISDN's star is fading rapidly. Still, IDSN is a good interim solution if you need higher speed than an analog modem can provide, and DSL and cable aren't yet available. To use ISDN service, you'll need an internal or external ISDN modem, or an ISDN router device and a network adapter. Your ISP can help you choose compatible equipment. In addition, you'll need the special ISDN telephone line wired into your home or office. DSLDigital Subscriber Line (DSL) service sends a high-speed digital data signal over the same wires used by your telephone line, while that line is simultaneously used for standard telephone service. This means that you can get DSL service installed without needing an extra telephone line. The most common DSL service is called asymmetric or ADSL because it receives data at 128Kbps to 1200Kbps and sends at a lower rate. (This is fine, because most Web surfing involves sending out a very small request and receiving a large amount of data back.) NOTE DSL varieties include Asymmetric, Symmetric, High-Speed, and DSL-over-an-ISDN-line, so you'll see the acronyms SDSL, ADSL, HDSL, and IDSL, or the collective xDSL. For this chapter, these distinctions are unimportant, so I'll just call it DSL. DSL service is not available everywhere yet, but it's spreading rapidly. However, DSL has at least one Achilles heel in that its availability is restricted by your distance from the telephone company's central office, and isn't available when the distance is more than a couple miles (as the wires run, not as the crow flies). DSL's reach can be extended by optical fiber lines and special equipment, but this is expensive for the telephone companies to install. DSL might never make it into rural areas. NOTE U.S. readers can see reviews of various DSL providers and check for DSL service availability at http://www.dslreports.com. DSL modems come in two varieties: External units connect to your computer through a network adapter or a USB cable. Internal units plug right into your computer. If your ISP uses external adapters, before you buy a network adapter, check with your DSL provider as they often include one in their installation kit. Also, before you decide to pay extra to get service for multiple computers, read Chapter 19 to see how you can share a single connection with all of your computers. Cable ModemCable modem Internet service is provided by your local television cable company, which sends high-speed data signals out through the same distribution system it uses to carry high-quality TV signals. Cable modem service has none of the distance limitations of ISDN or DSL. One criticism of cable service is that data speeds can drop during high-use times like the early evening, because everyone in a given neighborhood is sharing a single network "pipe." Recent surveys show, however, that cable subscribers on the average get 2.5 times the download speed of DSL subscribers.
Satellite ServiceSatellite Internet service uses microwave signals and small (roughly two-foot diameter) dish antennas to connect to an orbiting communication satellite. There are two types of satellite service: unidirectional, which receives high-speed data through the dish but transmits outgoing data by modem over a phone line, and bidirectional, which uses the satellite dish for both sending and receiving. Bidirectional service is the way to go! It's currently available in most parts of the world. Satellite's big advantage is that it's available wherever there's a good view of the southern sky (in the northern hemisphere), or northern sky (in the southern hemisphere). The disadvantages are that installation requires both a rocket scientist and a carpenter, the equipment and service plans can be expensive, and the system suffers from the same slowdowns that affect cable service. NOTE In the US, check out www.starband.com and www.direcway.com. In Australia, check www.telstra.com. In Europe, Southern Africa, the Middle East, the Indian subcontinent, and Southeast Asia see www.europestar.com. Satellite services are often resold through regional companies. Satellite service requires you to purchase a receiving dish antenna, a receiver, and a USB or network adapter to connect the setup to your computer. These devices will all be furnished by your ISP. For one-way satellite service, you'll also need to have a phone line near your computer. TIP To get the full scoop on satellite and wireless Internet service, check out The Complete Idiot's Guide to High-Speed Internet Connections by Mark Soper, published by Que. WirelessIn some major metropolitan areas, wireless Internet service is available through a regional network of small radio transmitters/receivers. Cell phone companies are getting into this in a big way, so it's going to spread rapidly. The wireless modem connects to a small whip or dish antenna, and data transfer rates typically are more than 1Mbps using setups with fixed antennae. NOTE Check www.sprintbroadband.com for more information. Wireless is similar to satellite service. You'll have to purchase a receiving dish antenna, a receiver, and a USB or network adapter to connect the setup to your computer. These devices will all be furnished by your ISP. You'll also have to pay for professional installation. Choosing a TechnologyWith all the options potentially available to Windows users for Internet access, making a choice that fits your needs and limitations can become a bit confusing. You should research the options provided by local and national ISPs, and then start narrowing them down. Table 8.1 summarizes the costs and speeds of the different ways for a single computer user to access the Internet. The prices shown are typical costs for the service in question after applying the usual discounts and special offers.
Remember that you have three or four costs to factor in:
Try to estimate how long you'll keep the service, and amortize the startup and equipment costs over that time frame when comparing technologies. If you are going to share the connection among several computers, plan to be downloading lots of large files, or will be playing games online, a faster service might make more sense, even if it's a bit more expensive. |
For more information on ISDN, xDSL, and cable modem service, 
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