The following simulation will show the waveform generated by different modulation techniques. Enter a short series of 0 and 1 bits that are to be transmitted using this technique and then press the Display button. You can easily view the different waveforms generated by the different techniques. The blue wave represents the base or carrier wave and the red wave represents the signal that would be sent to transmit the specified bit pattern. The purpose of a mo dulator- dem odulator is to convert the digital signal to a modulated sine wave.
Dialup modems can also perform phone functions such as dial, answer and hang-up.
There are many different types of modems in use operating at different speeds and conforming to different standards. To function, the modems on both sides of the connection must agree to use the same standard. This negotiation takes about 10 seconds for a V.34 modem and is usually heard as a series of squeals from your modem. Some systems may use a modem to connect to distant computers over a dedicated or leased line. This line is always connected between the two points.