E-List.Net
Internet Connection Tutorial

Plain Old Dial-Up

The vast majority of Internet users connect using an "analog" or "dial-up" modem. It's called "dial-up" because it dials a phone number just like you would to call somebody on the phone. Because a number of physical factors affect how well a dial-up modem works, let's take a quick look at the basics.

A dial-up modem converts the digital information your computer is sending to sound waves that travel across the phone lines. If you pick up the phone while someone is using the Internet you'll hear the modem at work. (See the "Modems" section at the end of this tutorial for more info.)

The frequency range of the normal human voice is 300 to 3500Hz. That's the range of sound where everyone's voice is understandable.  The telephone system is built to handle those frequencies primarily, and to deliberately exclude any other frequencies, thus limiting how fast information can move over the phone lines. (See the "Frequency" section at the end of this tutorial for more info.)

The Dial-Up Connection Process

Dial-up connections involve two modems: one connected to or inside your computer, and another modem somewhere at E-List.

When the modem at E-List answers your modem's phone call, the connecting process begins. This is called the "handshake." During the handshake you may hear beeps, swishes, and other noises as the two modems figure out how to communicate with each other.

During the handshake, the two modems agree on which language they will use to communicate. Most modems speak a few different languages, called "protocols." The protocol determines how fast your connection is.