Audicom PC Headset to RJ9/RJ10 Handset Y Splitter Training Box Adapter - Convert Dual 3.5mm Headphone to IP Phones Aastra Adtran BT Alcatel Lucent Avaya Interquartz Lazerbuilt Safecom (BPC35-TSTAB) Convert PC Stereo Headset Dual 3.5mm plugs to home or office phone with single 4P4C RJ9/RJ10 plug via this adapter box. Reduce clutter with single headset, and save money by buying a PC headset, or using your existing computer headset with home or office phone. Easy Setup, Plug and Play. Unplug handset cord from the phone base and plug it into the RJ line jack on adapter; Connect with the provided connecting cord to the phone base handset port and the line jack on adapter; Plug your PC dual 3.5mm jack headset to this adapter. Making a call - Pick up handset and dial the number using the telephone keypad; Answering a call - Pick up handset and answer to the call; Then you can talk on both your PC headset and handset; Ending a call - Place handset back on phone. Only works for some specific phones. Please see compatible phone models list in description below.