The plantronics a10 inline corded amplifier is a simple plug and play adaptor ideal for connecting all plantronics corded headset styles to compatible telephones it is a dedicated adaptor so there are no controls or switches to set or change and it uses plantronics quick disconnect to allow a choice of headset the plantronics a10 direct connect headset cable is for call centers that use both plantronics polaris brand headsets and amplified headset solutions like the m12 or m22 vista co