wiseGEEK: What is Dial-Up Internet Access?
Dial-up Internet access is a connection type that operates through a standard telephone line. By running the telephone line to a modem device in the computer and configuring it to dial a specific phone number, the computer can connect to the Internet. This connection type is usually inexpensive, but slow, and may not be adequate for users who use the web for multimedia and other high-bandwidth applications.
How It Works
This type of Internet access is offered through a number of Internet service providers (ISPs). Most ISPs lease a set of telephone numbers — sometimes local, sometimes national — that allow a computer to send information to network pipelines that feed into the Internet. Subscribers to the ISP normally pay a monthly or yearly fee for online access at any time of the day or night.
Before a person can subscribe to a dial-up service, he or she must have a computer and the right type of modem. A modem is a device that converts digital data into signals that can be sent over the phone line; some models fit into a free slot inside the computer, while others are external and connect to the machine with a cable. A telephone line is plugged into the modem to connect it to the phone system.
The modem is controlled by software in the computer which allows the user to set up a profile for the ISP, which will tell the modem what phone number to call and how to communicate with the service. Once the modem calls the phone number and makes a connection, a “handshake” takes place in which information is exchanged between the computer modem and the remote server. The subscriber chooses a username and password or has one assigned by the ISP, and this information is transmitted by the modem to allow the user to connect to the service.
Dial-up service is usually the least expensive type of Internet access, and may even be free in some places, although often with advertising added to it. It is also available to anyone who has a phone line, so there’s no need for a separate connection to be added to a home. Most computers already have modems installed, so there’s often no additional hardware to buy to start the service.
The biggest problem with dial-up Internet is that it’s slow. Due to the limited bandwidth, which is the ability for the modem to send and receive data, downloading large files can take a very long time. Most dial-up services operate no faster than 56 kilobits per second (kbps); downloading a file that’s several megabytes (MB) large would likely take several hours, which makes it too slow for streaming video or music. Saving copies (called “caching”) of frequently visited pages and other software tricks can speed up the experience in some cases, but most people who want to access a lot of multimedia will likely find the speed unsatisfactory.
Dial-up Internet also depends on the regular telephone line, which means that a home must pay for regular phone service to connect. The phone cannot be used for any other purpose, like voice calls, while the computer is using the line in most cases, and any disruption to the line will typically break the connection. In most situations, the user must dial in to the service each time he or she wants to get online, which means that the connection isn’t always on; it’s also likely to disconnect if the connection isn’t being used for some period of time. In addition, only one computer can use the phone line at a time.
Some of the most common, faster Internet options include cable and DSL (Digital Subscriber Line or Dedicated Service Line), although these alternatives may not be available in all areas. Like dial-up, DSL uses a regular telephone line, but it transmits data on a digital frequency rather than the standard analog so that the telephone and Internet can be used at the same time. Cable Internet service uses the same lines that bring cable television into the home. Both provide a 24-hour a day Internet connection, allowing subscribers to leave the computer actively connected to the Internet all of the time. These services can be much faster than dial-up but may also be more expensive.
In some places, Internet users may have other options for connecting, including satellite, fixed wireless, integrated services digital network (ISDN ), leased lines, and fiber optics like fiber to the premises (FTTP). These technologies are all broadband, meaning that they can transfer data at at least 1.5 megabits per second (Mbps). Unlike dial-up, broadband connections are usually much better at downloading multimedia content.