A modem normally has its own speaker. When you connect to the Internet and hear the modem dialing, it is this speaker that you hear the sound coming from. Computers only understand digital information, (pulse or non-continuous). Phone lines only transmit analog information, (continuous). Modems change a computer's digital information into analog waves that can travel through the phone lines to another computer. The other computer's modem then changes the analog waves back into digital information, so that the other computer can understand it. Modems are rated by how many bits of information they can receive in one second. Just because a modem is rated at 56Kbps does not always mean that it is going to be able to receive at that speed. Phone lines and your Internet service provider also play a big part in how fast your computer can receive information over the Internet. Some phone lines can only transmitting at about 28Kbps. For that reason, even though most Internet providers offer a 56Kbps connection, you're only going to be able to use their service at 28Kbps if your phone lines limit your connection speed.