Plantronics EHS APC-4 For Cisco Phones - 37978-01Electronic Hook Switches communicate electronically with the phone, eliminating the need for a HL10 handset lifter. Plantronics has several EHS adapters. Each adapter is unique to a specific telephone and wireless product: The APC 4 (Part Number 37978 01) is designed for our CS Wireless products, including the CS50, CS55, CS70, CS70N, CS351N, and CS361N. works with Cisco 7942G,7945G,7962G,7965G,7975G