INTERNET ACCESS

One of the most challenging aspects of the Internet is selecting a connection. Although most subscribers begin with dial-up connection, many soon explore high-speed Internet options. Home based LANs and wireless Internet access have become very popular.

A dial-up connection usesPOTS (plain old telephone services) to transport data between your computer and your ISP. With a dial-up connection, your computer’s modem essentially places a regular telephone call to your ISP, when the ISP’s computer “answers” your call, a dedicated circuit is established between you and your computer. This circuit remains connected for the duration of your call and provides a communication link that caries data between your computer and the ISP.

The modem, you use with this type of connection, converts the signals from you computer into signals that can travel over the telephone lines. The word “modem” is derived from the words “modulate” and “demodulate”. In communication terminology, modulation means changing the characteristics of a signal, as when a modem changes a digital pulse into an analog audio signal. Demodulation means changing a signal back to its original state, as when a modem changes an audio signal back to a digital.

Another option for Internet connection is cable Internet service; with it your cable TV company becomes your Internet provider. In order to provide this type of connection, satellite dishes are installed; usually they are installed for a community and are referred to as thehead-end. From the head-end, a cabling system branches out, offering both television and Internet access. Bandwidth of each cable is divided among three activities: TV channels, downstream data (the data you receive) and upstream data (the data you send).Cable Internet service plans offer speeds up to 6 Mbps.

With this connection your computer becomes part of a neighborhood data network and in this case two issues become significant: bandwidth and security. Unlike a dial-up connection, cable Internet service provides an always-on connection, which is particularly vulnerable to hackers and virus attacks. As for the second issue, the cable you share with your neighbors has a certain amount of bandwidth, and as more people use the service, it might seem to get slower and slower.

Other options, such as DSL and ISDN, could be chosen to get a high-speed Internet access. DSL (digital subscriber line) is a high-speed, digital, always-on, Internet access technology that runs over standard phone lines. It is one of the fastest Internet connections that’s affordable to individual consumers. Several variations of this technology exist, including ADSL (asymmetric DSL, with downstream speed faster than upstream speed). DSL is digital, so data doesn’t need to be changed into analog form and then back to digital as it does when you use a dial-up connection. A DSL can simultaneously carry voice and data, if permitted by DSL provider.

ISDN (Integrated Service Digital Network) is an all digital service with the potential to simultaneously carry voice and data. ISDN is not fast as DSL or cable Internet service but faster than a dial-up connection. A device called an ISDN terminal adapterconnects a computer to a telephone wall jack and translated the computer’s digital signals into signals that can t ravel over the ISDN connection. ISDN service is typically regarded as a high-speed Internet connection option for businesses that maintain small LANs.

There are two primary options for getting a wireless access of your home PC or LAN to the Internet: satellite Internet service or fixed wireless Internet service. Satellite Internet service uses a satellite to transmit computer data directly to and from a satellite dish, owned by and individual. A satellite modem connects the satellite dish to a computer. In many areas, satellite Internet service is the only alternative to a dial-up connection. But on the downside, satellite data transport is subject to latency delays of one second or more, which occur as your data is routed between your computer and the satellite that orbits the Earth 22.200 miles above the Earth. Satellite transmission and reception can be blocked by adverse weather conditions, which make this type of data transport less reliable than most wired options.

Fixed wireless Internet service is designed to offer Internet access to homes and businesses by broadcasting data signals over areas large enough to cover most cities and outlying areas. Wireless technologies have less latency than satellite Internet service and can offer connection speeds suitable for online gaming and teleconferencing.

Also it is possible to connect to the Internet through LAN. LAN provides a cost-effective way to share one Internet connection among several computers. School computer labs and businesses usually provide access over LANs. LAN Internet access is also feasible for home networks. A single cable Internet, DSL, ISDN, or satellite connection can be cabled into your home LAN and accessed by all its workstations.

Comprehension check. Indicate the paragraph where the following ideas are found in the text.

1. If a TV company has necessary equipment it can act as an Internet provider.

2. A lot of people soon switch from dial-up they use at the beginning to other types of connection.

3. If it’s allowed by provider, DSL can transmit both voice and data.

4. Satellite Internet service depends on the weather conditions.

5. With cable Internet service your computer is always connected to the Internet.

6. One of the cheapest ways to share Internet connection is LAN.