The Poly (formerly Plantronics) APP-51 Electronic Hook Switch (EHS) cable part # Poly 38439-11 or HP 85Q60AA communicates electronically with your desk phone giving your wireless headset call control. The APP-51 EHS allows ring alerts to sound in your headset as well as answer and end calls remotely.
This cable eliminates the need for a HL10 handset lifter. This cable works with Poly (formerly Polycom) desk phones and may work with additional manufacturers.