The APC-45 Electronic Hook Switch (EHS) provides you with freedom to move away from your Cisco SPA phone and answer calls from wherever you are - simply with a press of your wireless headset call control button. When a call is received, you will hear a tone in your ear. Simply press the talk button to answer the call. Press again to hang up. No more rushing back to your desk to answer calls. The Plantronics APC-45 Electronic Hook Switch (EHS) module enables wireless headset users to place or receive calls without the need to lift the handset of your Cisco phone.