Adapter cable with 3.5mm Headset jack to RJ9 Desk Phones Jack for Avaya, Cisco and more. Use PC Headset with most VOIP phones that have a RJ9/RJ10/RJ22 headset jack (Not compatible with RJ11). 1FT 3.5mm (1/8") Mono Male to RCA Female Jack Connector Aux Audio Adapter Cable.
eBay