AASTRA DT4x2 for BusinessPhone User Guide EN - Manual (Page 76)

Other Useful Features
BusinessPhone – Cordless DT412/DT422/DT432 76
To deactivate the Tandem configuration æ
Press.
#28#
Dial to log off the secondary phone.
For incoming calls:
•
The secondary phone cannot be called and the primary phone
works as a normal stand-alone phone.
For outgoing calls:
•
Both phones are treated as 2 separate extensions.
Transferring a call between members of a Tandem unit
R Press (see display).
å
Dial own directory number.
æ
Press.