HIS headset adapter cable plug into telephone's headset jack
For Avaya 96xx and 16xx series IP telephone including Avaya IP 1608, 1616, 9608, 9610, 9611, 9611G, 9620, 9620C, 9620L, 9621, 9630, 9630G, 9640, 9640C, 9641, 9641G, 9650, 9650G, 9650C, 9670.
This cable provides you with "on-hook" functionality so that you won't have to lift your telephone handset off the receiver for every call.