*Discontinued* by Plantronics.  No replacement

The Plantronics APV-6A Electronic Hookswitch (EHS) cable for Avaya Phones communicates electronically with the phone, eliminating the need for the HL10 lifter when using a Plantronics "CS" Series Wireless headsets (CS50, CS55, CS70N, CS351N, CS361N). 

Important: This cable is NOT compatible with the new CS540, CS510, CS520, you will need the APV-62 EHS cable instead

This cable works with the following Avaya model phones:

• 1408, 1416, 1608, 1616, 2410, 4630, 5410, 6416D+M, 6424D+M, 9404, 9406, 9408, 9504, 9508, 9608, 9610, 9611, 9611G, 9620, 9620C, 9620L, 9621, 9630, 9630G, 9640, 9640C, 9640G, 9650, 9650G, 9670

Also See Avaya direct connect headset page for reference

Note:

Avaya 1600/9600 Bluetooth Option Module (p/n 700383789) available
Avaya 24XX and 54XX phones require firmware 4.0 and greater
Avaya 46XX and 56XX phones require 1.8 firmware or greater