To change your default outbound line : This feature sets the preferred outbound line when the headset call control button is pushed while all lines are idle.
With the system idle, you can change your default outbound line by pressing the desired
outbound base button until it flashes green four times.
You can also change the default outbound line using the Plantronics Control Panel by going to
Start > Programs > Plantronics > Plantronics Control Panel > Device Settings > Base