AASTRA DT4x2 for BusinessPhone User Guide EN - Manual (Page 63)

63 BusinessPhone – Cordless DT412/DT422/DT432
Messages
Send message
You call an extension and receive the busy tone or no answer.
Two possibilities exist:
1 Callback message (Call Me message)
2 Voice message
Callback (Call Me message) 9#
Press to send a Call Me message.
Voice message
If you want, you can send a Voice message instead: 99
Press and speak.
*
Press to play-back.
9
Press and speak to re-record.
#
Press to send.