This amazing adaptor converts the standard 3.5mm smartphone plug to an for Aastra RJ9, RJ10, or RJ22 handset plug, allowing you to use your favorite smartphone headset with your for Aastra office phone.The adapter outputs binaural sound for stereo headsets, meaning you will hear sound out of both ears.Convert 3.5mm OMTP smartphone plug to single 4P4C RJ9/RJ10 handset/headset plug.Save money by buying a smartphone headset, or using your existing one with your office phone& 39;s headset jack.This adapter will not work with for Apple EarPods and other CTIA based headsets.Works best when paired with an amplifier.For optimal use, please plug into the headset jack on your phone. The handset jack usually causes audio distortion.Compatibility:This list is not all inclusive. Updated 3/1/17.Incompatible Phones:For Avaya 1100, 1200, 1600, 2000, 4600 and 9600 SeriesFor Cisco 7902, 7905, 7910, 7911, 7912, 7920, 7921For Nortel 1140T and Visa 350For Polycom PhonesFor Shortel IP 230For Uniden Dect2088, TRU9496For Western Electric 6250Incompatible Headphones:For Apple EarPods.Compatible Phones:For Aastra/Packet8/8x8 480e, 480i, 53i, 55i, 57i, 57iCT, 6753i, 6755i, 6757i, 9112i, 9133i, 9143i, 9480iFor Allworks 9212For AltiGen IP Phone 500, 510, 600, 705, 710, 720For Avaya 4500 Series IPFor ESI 48-Key IP Feature Phone and 48-Key Digital Feature PhoneFor GE Model 2-9451For Inter-TelFor Lucent 8410DFor Mitel IP 40XX, 41XX, 5000, 50XX, 5140, 52XX, 53XX, 5550For NEC Dterm Series EFor Norstar T7316E, M3904For Nortel IP 1120E IP, 1140E IP, 1150E IP, 1230, i2002 and i2004For Nortel Meridian Norstar Northern TelecomFor Panasonic HybridFor Plantronics T10For Possum SeroFor Shoretel ShorePhone IP ModelsFor SiemensFor Splicecom PCS 520For Talkswitch IP Phone, TS-600For ToshibaFor 3COM 3102, 3103Compatible Amplifiers:For Plantronics S-12, M22, A20, MX10, TSB, AP15Item Name: 3.5mm to RJ9 CableLength: 20cm/7.87" (Approx.)Notes:Due to the light and screen setting difference, the item& 39;s color may be slightly different from the pictures.Please allow slight dimension difference due to different manual measurement.Package Includes:1 x 3.5mm to RJ9 Cable