Plantronics APT-31 Savi and CS500 series Electronic Hook switch (EHS) cable for Avaya Phones. compatible with the following Plantronics wireless headsets:

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 works with the following Avaya phone models (do not order if your phone model is not listed):

Tenovis T3 classic, T3 IP classic, T3 IP II classic, T3comfort, T3 IP comfort, T3 IP II comfort, T3 compact, TH 13, TM 13, TS 13, OS13, OS 33

Old Poly part # 37820-11

New HP part # 85Q84AA