Electronic Hook Switch- communicates electronically with the phone. For use with Savi and CS500 series headsets on Avaya 2420, 4610, 4610SW, 4620, 4620SW, 4621SW, 4622SW, 4625SW, 4630SW, 5420, 5610, 5620
Learn more about Plantronics APV-66 EHS (38633-11)