If you are having trouble with the Intercom service, make sure you have taken the following hints into consideration.
Make sure you've set the volume control for your sound card properly. See Using the Windows Volume Control Accessory.
Make sure the microphone and speaker levels are set correctly. See Adjusting the Microphone and Speaker Levels.
Don't speak too closely into the microphone. It also helps to direct your speech slightly to the side of the microphone.
Use the Sound Recorder multimedia accessory to make sure you can record sound and play it back.
Make sure you're using the right Sound Compression setting. If the other user is on the same network (LAN) with you, select None.
If you switch compression methods—None, GSM—during an Intercom session, don't speak while you are switching. This can degrade the sound quality.
If the sound card on either computer is already being used by another application—for example, recording or playback—you won't be able to begin your Intercom session until the other application has been closed.
If you have a CD player playing on the guest side, the host side might also hear the sound from the CD. There is a way to stop this in "Volume Control." See Using the Windows Volume Control Accessory.
Intercom is not supported with Dial Direct connections.
Note: The Intercom button will not be available unless you have a sound card installed.