Plantronics Savi/CS500 series 3.5mm EHS cable for Panasonic KX-UT phones (KX-UT670, KX-UT133, KX-UT136 only).  This EHS adapter allwos  communicates electronically with these Panasonic phones, eliminating the need for the HL10 lifter. Only compatible with these Plantronics Savi and CS500 models:

Plantronics CS540, CS510, CS520 , Plantronics Savi WO100,   Plantronics Savi WO200,   Plantronics Savi WO300  Plantronics Savi WO350 , Plantronics Savi W740,  Plantronics Savi W710 , Plantronics Savi W720 ,  Plantronics Savi W730 ,  Plantronics Savi W745

This cable only works with the following Panasonic phones:

Panasonic KX-UT670, Panasonic KX-UT133, Panasonic KX-UT136

Do not order this cable if your model is not listed.  You will need the HL10 lifter instead.  Also see Plantronics/Panasonic headset solution guide

Old Poly part # 84757-01

New HP part # 85R17AA