Does your Plantronics CS540 squeal or have static during calls? If your CS540 squeals or has static during a call that both you and your caller hear, try re-subscribing the base to the headset. Manual Over-the-Air Subscription: 1) With your Plantronics CS540 idle and your headset undocked, press and hold the subscription button (Labeled 1) on the base for three seconds. The Power on/subscription light … Continued