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Hold:
Click the button
to hold the current call, press
to resume
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
, handsfree
or
headset
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