Plug the other two cords of the Plantronics APC-4 Hook Switch cable into the back of your Cisco phone into the HEADSET port and AUX port. Note: If you go to turn your CS55 headset on and you get a triple beep tone, follow the CS55 pairing guide. Note: Within your Cisco phone you may need to enable the hook switch mode by the steps below.
Works great with laptop. We replaced our desk top phones with web based program and by using this adapter I was able to keep using my Plantronics headset. Not able to answer the web based program handsfree but otherwise headset works as if connect to phone.