Sony CAV-M1000ES - Manual (Page 27)

Setting up the Keypad
27 US
3 Insert the top of the Keypad onto the mounting
bracket first, in the direction of the arrow 1 until
it clicks, then push the bottom of the Keypad onto
the bracket in the direction of the arrow 2.
4
Fix and tighten the Keypad mounting screws as
shown below.
5 When you have finished mounting the Keypad,
check that it operates properly.
Removing the Keypad
1 Remove the screws that hold the Keypad and the
Keypad mounting bracket.
2
Press and hold the edge of the upper-side of the
Keypad tightly. Pull the lower part of the Keypad
away from the Keypad mounting bracket first,
then pull the upper part of the Keypad out
slightly, lifting it in the direction of the arrow, as
shown below.
Note
You may need some extra effort to remove the Keypad from
the wall since there are various kinds of junction boxes, and
the installation environment of the Keypad differs.