Types of Internet Connections
Now many different technologies are available to connect Internet. Some of them are:
- Dial-up connection
- ISDN connection
- Cable Modem connection
- DSL and ADSL connection
- Satellite connection
- Wireless connection
Short description about these technologies are given below:
The dial-up connection is still used by many Internet users throughout the world. It is simple and reliable so, it is very popular types of connection. To use this service, we need a telephone line, computer system, a modem and Internet service (username and password from ISP).
A modem is a device that provides an interface between the computer and communication lines, such as cable or phone lines. It converts the computer’s digital data into an analog signal so that it can be carried via the communication lines. This process is called modulation. When an analog signal arrives at the receiving computer, the modem then demodulates (converts) the signal back to digital. This technology is symmetric because both the upstream and downstream data rates are the same.
Dial-up access is still used by the majority of Internet users because it is readily available. It is also relatively inexpensive than other connections. We have to pay just monthly ISP fee. However, this technology also has some drawbacks. It engages (ties up) our phone line while we connect the Internet. It’s also slow compared with the newer broadband technologies and it is being disconnected from the Internet time to time. Because of these disadvantages, there is a steady movement of users to fast access, such as ADSL, cable modem satellite and other wireless connections.
Integrated Services Digital Network (ISDN)
Integrated Services Digital Network (ISDN) provides the fast Internet services than dial-up. It has upstream speed in 64 kbps and downstream speed 128 kbps. ISDN is a type of technology that can simultaneously carry digital voice and data transmissions. It works by using a portion of existing phone lines to send and receive digital communications. The data is sent using D or B channels that run simultaneously over a single phone line using different channels. To carry the data means, you can access the Internet and talk on the phone at the same time.
ISDN is faster than dial-up but is no longer considered competitive with the newer technologies, such as cable modem, ADSL, etc.
Cable modem connection
The cable modem is a technology that uses a cable TV connection rather than a phone line to connect to the Internet. The cable is attached on an Ethernet device in your computer. It’s service costs more than dial-up connections. The bandwidth of the coaxial cable used is significantly greater than that used for a standard phone line. It has the upstream speed of 500 kbps and downstream speed in 2000 kbps. But, this speed depends on a number of factors. One of the most important facts is that the bandwidth is a shared resource. If everyone in the neighborhood signs up for cable modem service and uses it simultaneously, the speed goes slow down.
ADSL and DSL connection
Digital Subscriber Line (DSL) is a technology that provides high bandwidth for data to travel. It has very fast Internet access and data transfer rates. The ADSL is variation od DSL and it is widely used technology. At the time of this writing, Nepal Telecom is providing ADSL service only for Kathmandu valley and now it is being more popular. ADSL is called Asymmetric DSL because it has different upload and download speed.
DSL technology works by taking advantage of the unused frequencies on copper phone lines to transmit data. DSL can transmit voice and high-speed data simultaneously over a single phone line. This enables us to carry on a conversation and surf online-all at once.
To connect the Internet through ADSL some basic equipment are required: a network interface card (NIC), an ADSL modem, telephone line etc. ADSL is an increasingly cost-effective method of getting fast access. Setup costs are usually relatively low.
Difference between ADSL and Dial-up Connection
|1. ADsL modem is used with regular telephone line.||1. Dial-up modem is used with regular line.|
|2. It uses digital frequency to transfer data.||2. It uses analog frequency to transfer data.|
|3. This connection is not depended on the telephone cost you have to pay for ADSL package.||3. You have to pay phone call charge whatever time you connect the Internet.|
|4. Not to pay Dial-up fee for every time connecting the Internet.||4. Dial-up fee have to pay for each time connecting the Internet.|
|5. It is more faster that Dial-up||5. It’s speed is slower than ADSL.|
Some Drawbacks of ADSL technology
- The user near the service providers control office can get high quality service but the user from their central office cannot get good service.
- Data receiving rate (download) is faster than data sending rate (upload).
- This services is not available in every location. In the contest of Nepal, this service is available such as Biratnagar, Nepalgunj and Kathmandu valley and otehr major cities, Bhairahawa and Baglung.
Dial-up, ADSL and cable modem services are available only in the city area. The rural people can’t take advantages from these broadband services. For those people, the satellite is the best technology to use the Internet.
Satellite Internet access works by sending our request from the computer system, via a satellite dish, to a satellite approximately 25 thousand miles above the earth. This signal is sent to the ISP’s hub, in which it routes the request through the Internet’s backbone to the appropriate location. The information such as a web page is routed back via the reverse route and then beamed down to the satellite dish, at which it is downloaded into our computer. This all process takes place at a significantly faster speed than either dial-up or ISDN. Its upstream speed is 60Kbps and downstream speed is 200Kbps-400Kbps.
Nowadays, most broadband satellite service provides two-way service, in which information is both uploaded and download via satellite broadband provides an option for those who can’t get DSL or cable modem services. The advantages of satellite include its almost universal availability, fast speed, and the cost savings of not having to install a second phone line.
There are some drawbacks of a satellite. It takes more cost to set up at the first time. The dish is expensive and it requires professional installation. The reliability of satellite service depends on whether and solar conditions. For example, an upcoming storm can prevent uploading or downloading information.
The new technology for connecting to the Intenet is fixed wireless. This technology involves sending data via radio signals. The main disadvantage to this service is available because users need to be within a few miles from the signal is transmitted (access point).
Wireless services use a variety of frequencies and technologies to send and receive data. As a result, data transfer rates can differ significantly. the point where the signal originates also affects the connection speed. Because of the difference in speed, some wireless ISPs structure their pricing plans based on the data transfer rate. For example, RUIM Card of Nepal Telecom, U-Sim of United Telecom Nepal etc.