Audicom Telephone Training Adapter Y Splitter with RJ9/RJ12 Plug Connections for Corded Headset or Handset for Toshiba Aastra Nortel Nec Mitel ShoreTel InterTel Talkswitch Iwatsu IP Phones(YTRJ-STAA) Can plug either into handset port or headset port Handset or Headset Splitter, Complete with RJ9/RJ12 plug Great use for call center / telephone marketing trainings Easy setup, plug and play Only works for some specific phones. Please see compatible phone models list in description below