Not sure if it is a production error or by design, but there is no stereo on this device. I worked around it by plugging the minijack of my headset halfway in. Also, customer support on Plantronics had a hard time finding this product in its system since it presumably is very old, and they told me that it was a binaural, not stereo, product. However, the mini-jack to plug into my PC looks like a Stereo plug.