AASTRA DT4x2 for BusinessPhone User Guide EN - Manual (Page 78)

Other Useful Features
BusinessPhone – Cordless DT412/DT422/DT432 78
Doorphone
The doorphone is used to monitor the admission to your company,
i.e. you can open the doorlock from your Cordless.
Answering Doorphone calls æ
Press.
You will be in speech connection with the calling party.
Opening of the doorlock
After you have answered the Doorphone, you can open the door
making an inquiry to the door-opener’s directory number.
R Press (see display).
å
Dial the door-opener’s directory number.
Please ask your system administrator for the number.