Panasonic KX-TG9541 Operating Instructions Manual page 53

n While your headset is on a landline call:
To join the conversation with the handset, press
M N.
R An available line is automatically selected. To
change the line selection mode, see page 16.
Adjusting your headset receiver volume
Base unit
Press MDN or MCN repeatedly while using your
headset.
For assistance, please visit http://www.panasonic.com/help
Using Bluetooth Devices
53