Panasonic KX-TG2584S - Manual (Page 76)

You can hang the cordless handset on your belt or pocket using the belt
clip.
To attach the belt clip To remove the belt clip
Plugging an optional headset into the cordless handset allows a hands-free
phone conversation. Please use only the Panasonic KX-TCA88 headset.
To order, call the accessories telephone number on page 2.
Connecting the optional headset to the cordless handset
Open the headset jack cover, and connect the optional headset to the
headset jack as shown below.
76
Optional Headset
When the optional headset is connected to the cordless handset,
make sure to use the headset to talk with the caller. If you want to
have a normal cordless phone conversation, disconnect the
headset.
Headset Jack
Belt Clip