Avaya 3600 Series - Manual (Page 11)

Avaya Inc. Desktop Charger, Dual Charger, and Quad Charger User Guide
The WT Headset
AVAYA offers optional headsets for use in noisy environments
or if you need to have your hands free while talking on the WT.
To use the headset, simply plug it into the jack on the bottom of
the WT. The headsets offered by AVAYA are specially designed
to work properly with the WT. We do not recommend using other
headsets.
21-300632, Issue 1, July 2005 Page 11