AASTRA 4420 IP Basic (SIP) for MX-ONE User Guide - Manual (Page 42)

Messages
Dialog 4420 IP Basic 42
Order MMW to another extension
In idle mode: *31* z #
Dial, enter the extension number and press.
Press.
The Message Waiting key lights up on the called extension.
Cancel MMW to another extension #31* z #
Dial, enter the extension number and press.
Press.
Message Waiting (optional)
If your phone is assigned with this feature and if it is diverted to an
interception computer, the Message key lamp is on when there are
messages stored for you in the computer. The messages will be
printed out on a printer connected to the computer.
To print out messages
Message
Х Ф
Press.
If you find that the notification of Message Waiting is intrusive or
you want to shut off the notification: #91#*
Dial.
Acknowledgement tone.