Broadband and dial-up are two different methods for connecting to the Internet. With the development of the Internet and the parallel development of computers as viable business tools and as useful home information management tools, connection to the Internet became a priority, and dial-up was a convenient way to use the existing telephone infrastructure to accomplish it. Broadband connections also operate over the telephone system infrastructure, but use unused telephone lines, thus freeing users from the limitations of dial-up. Broadband and dial-up Internet connections are both available to consumers, but broadband is much more popular.
A dial-up connection to the Internet requires that the digital code sent by a computer be translated into an analog signal that can be sent over the telephone line. When these signals are received by the computer at the other end, they must be translated from analog back into digital code. The computers at either end of the phone line must be equipped with special devices called modems to perform the translation to and from digital code. The fact that the computer code is sent as an analog signal limits the speed with which code can be transmitted to the capabilities of the phone system. In general, the greater the size of the file being transmitted, the longer it will take.
The earliest modems available commercially offered low speed data transfer rates, and the modems available rapidly became faster and more sophisticated until they reached a data transfer rate of 56 kilobits, commonly called 56k. This is theoretically the fastest dial-up connection available because of the limitations of telephone systems.
The convenience of using an already-existing infrastructure, as opposed to having to build a new one, was accompanied by the twin drawbacks of being costly and time-consuming. Each Internet session had to be established separately: the phone line would be accessed, the ISP's phone number dialed, and a separate connection established for each Internet session. This process took time, and the actual transfer of data was slow and could be made slower by a number of variables. For example, the quality of the signal could be degraded by such things as the distance between the modem and the telephone company's equipment and the number of subscribers sharing the exchange.
In addition to the time lost to establishing a connection and slow data transfer rates, dial-up Internet access was inconvenient for those households that had only one telephone line. During an Internet session, they couldn't place or receive calls; in addition, if anyone in the household lifted the telephone receiver from the hook, the Internet connection would be interrupted.
Another factor adding to the cost of Internet use was the fact that users had to pay connection charges to the telephone company for the time they were connected to the Internet, as well as usage charges imposed by their ISP, usually based on total connection time. Many users reported total monthly costs in excess of $250 US Dollars (USD).
Broadband and dial-up Internet connections differ in a number of ways. While both employ telephone lines, broadband doesn't share a line with a telephone. Users aren't deprived of the use of their telephone while using the Internet and there's no payment to the phone company for the amount of time spent on an Internet connection. In fact, with a broadband connection, the Internet connection is constant – once installed, the connection is never broken, so that all a user needs to do is open a browser window; no time is lost establishing a connection.
The speed of data transmission is another critical difference between broadband and dial-up Internet connections. While dial-up connections are essentially limited to the 56k provided by the most modern dial-up modems, broadband connections are capable of much faster speeds, in some cases more than a thousand times faster. Most games and other entertainment applications can only be used with a broadband connection.
The cost to the consumer of using dial-up has decreased significantly because ISPs first stopped charging for time spent connected to the Internet, and then lowered their rates to retain customers. In addition, most users can take advantage of flat-rate telephone use plans, so they don't pay the telephone company any more than a flat monthly fee for telephone use.