-This page is being edited by Michael Kim-

Dial Up

Dial-up is the most cost efficient out of the connection types (its inexpensiveness is because it uses existing phone lines without splitting the line channels), but it is also the least convenient. To use dial-up, the user must have access to a telephone modem, which is a device that connects a computer to the telephone system and is capable of converting data into sounds and sounds back into data. The user’s ISP (Internet Service Provider) provides software that controls the modem. To access the Internet, the user opens the software application, which causes the dial-up modem to place a telephone call to the ISP. A modem at the ISP answers the call, and the two modems use audible tones to send data in both directions. When one of the modems is given data to send, the modem converts the data from the digital values used by computers— 1s and 0s (binary)—into tones. The receiving side converts the tones back into digital values. Unlike dedicated access technologies, a dial-up modem does not use separate frequencies, so the telephone line cannot be used for regular telephone calls at the same time a dial-up modem is sending data I.e. - cannot use the phone while using the internet on a dial up (which turns out to be really annoying. Believe me. I know.). Because dial-up uses tones to transmit data, it is usually very slow (no kidding here) and (makes screech beepy noises when connecting) - which (I believe...) is called a 'handshake' and this sets the communication parity prior to the connection to ensure no data is lost.

source: http://encarta.msn.com/encyclopedia_761579729/Internet.html#p9