18
Hold
：
Click the button
to hold the current call, press
to reseume
Transfer :
Click the button
to enter the establish transfer
interface
Mute:
Click the button
to mute,
to resume.
Video call :
Click the button
to send a video request/close the
video
Answer mode:
to switch handset
, handfree
or
haedset
mode
Extend key :
Click the button
to open the extended icons,
to close.
Conference :
Click the button
to enter the establish
conference interface
Record :
Click the button
to start record,
to stops
