RJ9 4P4C Male Plug to 3.5mm Female Headset Phone Converter Adapter
3.5mm TRRS (Female) rj-9 4P4C (Male). Use PC Headset with most VOIP phones that have a RJ9 headset (Not for RJ11). Adapter cable with 3.5mm Headset to RJ9 Desk Phones forCisco and more. Don'for t need to worry about the compatibility.