Panasonic KX-NT551 Quick Reference Manual page 22

Wall Mounting
2
Fasten the wall mounting adaptor(s) to the base with the screw(s).
(Recommended torque: 0.4 N·m [4.08 kgf·cm] to 0.6 N·m
[6.12 kgf·cm])
3
Connect the cables to the unit, and run the cables through the wall
mounting adaptor, as shown in the illustration below.
4
Drive the screws into the wall either 83 mm or 100 mm apart, and
mount the unit on the wall.
Example: KX-NT553/KX-NT556 with KX-NT505
3
40 mm or less
2
22
AC adaptor
4
Drive the screw
Ethernet cables
to this point.
Washer
83 mm
100 mm