AT&T ML17959 - Manual (Page 14)

Getting started
9
Installation options
If you want to mount your telephone on a wall, connect the telephone base
to a standard dual-stud telephone wall mounting plate. If you do not have
this mounting plate, you can purchase one from many hardware or consumer
electronics retailers. Professional assistance may be required to install the
mounting plate.
Tabletop to wall installation
To install your telephone base in the wall installation position, make sure you
first unplug the power adapter from the electrical outlet and the telephone
line cord from the wall outlet.
Hold down the switch hook on the telephone base, then slide the handset
tab upwards to remove it from the slot. Rotate the handset tab 180 degrees.
Push the handset tab down into the slot until it locks into position. 1.
Press in the direction indicated by the arrows to release the mounting
bracket. Remove the mounting bracket from the telephone base. 2.
option 1: Low tabletop position option 2: high tabletop position
Switch hook