AASTRA DT4x2 for MD Evolution User Guide EN - Manual (Page 44)

Outgoing Calls, Busy/No-Answer
MD Evolution – Cordless DT412 / DT422 / DT432 44
Outgoing Calls, Busy/No-Answer
Automatic Callback
You call an extension and receive busy tone or get no answer. This
can also be used if no external line is free: 1
Press.
Verification tone. æ
Press.
You are called back if the extension finishes the ongoing call or the
next time the extension finishes a new call. You have to answer
within eight seconds otherwise the Callback service is cancelled.
Busy Extension
You call an extension and receive busy tone.
Intrusion
You can intrude on an ongoing call on a busy extension (if this
function is allowed). 3
Press to intrude.
Intrusion tone is heard and a three-party call is established. When
the called extension replaces the handset and you keep off hook,
the called extension will be recalled automatically.
Note: If you still hear the busy tone, then your extension
does not have the authority to intrude or the desired
extension is protected against Intrusion.