Scroll down to see how to do this in Symphony 1.5
In Symphony 2.0:
By default, you will enter a meeting unmuted and with your video off. During your meeting, control your audio and video by clicking on Settings in the upper right (figure 1):
Figure 1 Meeting settings
In Symphony 1.5:
During a Symphony meeting, access audio and video options by clicking on Settings in your menu (Figure 1):
Figure 1 Meeting Settings
You can select the camera, microphone, and speakers used for your voice and video conferencing.