Summary

DMP Alarm Graphic Keypad - modeled to work with model 7872 but is probably compatible with all similar DMP keypad models.

j-box adapter - allows you to easily mount keypad to standard USA style electric j-boxes. Holes and punchouts for single, double, triple-gang and 4-square boxes.

surface mount backbox - same as above but taller to give you room to connect the wiring harness to the field wiring inside the adapter

wiremold / metallic raceway backbox - same as above but even deeper and has a space to attach the the box to metallic surface mount raceway entering the box from the the top center. If you need a side or bottom entrance and lack the skill to modify the fusion 360 files yourself let me know and I'll make one up (fast service not guaranteed).

Image attached for which punchouts are for which purpose. To remove a punchout you should be able to just stab the tip of a screwdriver through the appropriate slot and give it a wiggle.

When attaching to a j-box it is typical that the various "gang" connectors will use a #6 machine thread screw and the 4-square screw should be a #8.

For all variations you can use the longish #6 coarse thread screws that DMP provides with the keypad if you want but they will stick out the back of the adapter quite a bit unless you cut them shorter (or you're ok with them penetrating the surface behind). Alternatively four #6 x 3/8" screws should be just about perfect, though you might have to blunt/snip the pointy tip when using the j-box adapter if you don't want the very tip sticking out the back. Use only the DMP provided #6 screws or dimensionally equivalent substitute to attach keypad bracket to adapter. Using larger screws may short against the circuit board.

How I Designed This

Direct measurement from keypad in hand to a model in Fusion 360. Fusion 360 (.F3D) and STEP files included.