AASTRA 4222 Office for MX-ONE (TSE) User Guide EN - Manual (Page 72)

Settings
Dialog 4220 Lite/Dialog 4222 Office 72
Ring signal volume
Use the Volume keys to adjust the ring signal volume when the phone is
idle or ringing. Adjusted volume is stored.
ì
Press to adjust the volume.
On the Dialog 4222 Office phone, a volume symbol is shown for a few
seconds (replacing your extension number).
Mute ring signal
You can suppress the ring signal for an incoming call.
É
Press to supress the ring signal.
The ring signal is switched off for the current call, and your phone is
automatically set to Silent Ringing (see below).
Silent Ringing
If you do not want to be disturbed by the ring signal but still want to
answer an incoming call, you can switch off the ring signal. Incoming
calls are only indicated by a flashing line lamp and display information.
When the phone is in idle mode, or when ringing:
É
Press to switch off the ring signal.
The Mute key lamp is switched on to indicate Silent Ringing. The ring
signal will automatically be switched on the next time you lift the
handset or press any key.