Panasonic KX-TD1232NL Installation Manual page 120

3.2 ISDN Line Connection
3.
Hook the cabinet to the main unit and slide the cabinet to the left until it is secured.
4.
Loosen the outside screw and slide the cover to the right.
5.
Secure the inside screw (included) to fix the cabinet to the main unit.
Note
Be sure to fix the inside screw to the main unit, or the unit may not work properly.
120
Outside screw
Inside screw
ISDN Installation