Modern PCs are usually equipped with a "sound card", which allows sounds to be captured and reproduced by the computer. EchoLink relies on the sound card (or built-in equivalent) to exchange audio with other stations on the Internet.
The most common configuration for EchoLink is to connect a pair of amplified speakers to your computer's "speaker out" connector, and to plug a microphone into the "mic in" jack. Many other multimedia programs work with this same configuration.
On Windows, Playback Volume is adjusted in two different places:
On Windows, Recording levels are adjusted on the Recording tab of the Sound control panel. To open this panel, right-click the speaker icon in the lower-right corner, and choose "Recording Devices".
The Recording tab shows a list of sound input devices. If you have a device with more than one jack (for example, Microphone and Line In), each jack might be listed separately. The one with the green check mark is the default device. To adjust the recording levels, right-click the name of the device and choose Properties, then choose the Levels tab. If the device has adjustable levels, one or more sliders will be shown.
If you want to use a different device (or jack) for EchoLink, you can change the default device here, or go to EchoLink's own Setup page, choose the Audio tab, and choose a specific device from the list of Input devices there.
While you are speaking with another station using EchoLink, watch the Audio Level Meter near the bottom of the screen as you speak. The meter should jump at least into the yellow area on voice peaks, but should not go full-scale. Adjust the Microphone slider (described above), if necessary.