Audicom Pc Headset Adapter Computer Stereo Headphone Dual 3.5mm to Rj9/Rj10 Phone Jack Converter for Aastra Shoretel Cisco E20 Polycom 335 VVX400 Digium D40 D70 Altigen Telephone IP Phones(PC35-STAC) PC Stereo Headset Adapter Converts Dual 3.5mm to RJ Plug Still get great quality stereo sound from headset via this adapter All functions on headset and phone would function same Easy Setup, Plug and Play Only Work with Some Specific Phones in Description. Only buy it if you have one of the phone models listed in description below.