I'd stick with "serious" colors such as black and gray, maybe a touch of red to suggest alarms, and the font matters too. A substantial blocky font that suggests strength etc. If the company name has a word in it that you can turn into an icon, that can be useful (like Firefox's fox etc). Any icon or shape that suggests strength or power is good. ADT's logo is in the shape of a Stop sign, which subconsciously suggests "Hold it right there, Buster!"
-edit typo
... View more