Panasonic VA-12020 Operating Instructions Manual page 39

Up to 4 single line telephones can be connected to this system.
In case of a power failure, the single line telephones only can be used.
make
To a call
For automatic line selection, see page 19 concerning 'Automatic Outside Line Selection.
With a single line telephone you can take advantage of the following features
In case of, a power failure, the key telephones cannot be used. If your system have power
failure unit and single line telephones, the single line telephones only can be used.
1. Lift handset
* You will bear the intercom
2. Press 9 for automatic line selection, or 8 for specified line
dialing and the desired line number
3. Dial the telephone number
4. Speak when answered
Making and answering intercom calls
Door box call (75 or 76)
Door opener function (78 or 79)
Outside call hold (Flashing)
Hold recall
3 8
tone from handset