Any terminal to activate an internet service on it require an internet connection from an Internet Service Provider. To have a connection one needs to contact the Internet Service Providers. There are several Internet Service Providers (ISP) in each locality. There are some nominal charges that you need to pay to the ISP for the installation of the connection and for the rent (either monthly or annually). Depending on the requirement you choose any one of the available options. If you need a high speed dedicated network then you can opt for a high bandwidth broadband or leased line connection.
Figure 4.6: Internet and its peripherals
If you need to have connection on a single PC then you choose a low bandwidth or dialup connection. For small services at your hand, you can even have mobile phones connected to your Internet. There are many ways to get connected to the Internet. You can get internet connection in any of the following ways-
Through dial-up connection-
User is supposed to get connected to the internet after dialling up the number used for connection. This is useful if your network is either confined to small group of computers or for a single PC.
Through leased lines-
In this connection a dedicated line is laid specifically for connection.
Though broadband-
In this connection you can get a broadband connection which provides a high bandwidth for the internet connection. This also provides a good data speed.
These days even wireless connections are available. For this you need to have a Wi-Fi card attached to your computer which can be useful if you do not have proper place to lay down the wires.
To connect to the Internet you need a PC (personal computer) with requisite software including a browser, a telephone connection or a leased line, and a modem, which allows the PC to communicate with other computers. There exist several ways to connect to the internet. Following are these connection types available:
• Dial-up Connection
• ISDN
• DSL
• Cable TV Internet connections
• Satellite Internet connections
• Wireless Internet Connections
Dial-up Connection- 
Dial-up connection uses telephone line to connect PC to the internet. It requires a modem to setup dial-up connection. This modem works as an interface between PC and the telephone line. There is also a communication program that instructs the modem to make a call to specific number provided by an ISP.
Dial-up connection uses either of the following protocols: Serial Line Internet Protocol (SLIP), Point to Point Protocol (PPP)
Figure 4.7: Internet Access Dial-up Connection Modem
ISDN-
ISDN is acronym of Integrated Services Digital Network. It establishes the connection using the phone lines which carry digital signals instead of analog signals. There are two techniques to deliver ISDN services: Basic Rate Interface (BRI) and Primary Rate Interface (PRI).
Figure 4.8: Internet Access ISDN Modem
DSL (Digital Subscriber Line)-
DSL is acronym of Digital Subscriber Line. It is a form of broadband connection as it provides connection over ordinary telephone lines. Following are the several versions of DSL technique available today:
• Asymmetric DSL (ADSL)
• Symmetric DSL (SDSL)
• High bit-rate DSL (HDSL)
• Rate adaptive DSL (RDSL)
• Very high bit-rate DSL (VDSL)
• ISDN DSL (IDS)
All of the above-mentioned technologies differ in their upload and download speed, bit transfer rate and level of service.
Cable TV The Internet connection is provided through Cable TV lines. It uses coaxial cable which is capable of transferring data at much higher speed than common telephone line. The following diagram shows that how internet is accessed using Cable TV connection:
Satellite Internet Connection-
Satellite Internet connection offers high speed connection to the internet. There are two types of satellite internet connection: one way connection or two-way connection. In one way connection, we can only download data but if we want to upload, we need a dialup access through ISP over telephone line. In two-way connection, we can download and upload the data by the satellite. It does not require any dialup connection. The following diagram shows how internet is accessed using satellite internet connection:
Wireless Internet Connection-
Wireless Internet Connection makes use of radio frequency bands to connect to the internet and offers a very high speed. The wireless internet connection can be obtained by either Wi-Fi or Bluetooth.