Hi IVB;
Here is the way I did this for my friend's house. This also gives you a lot of future options for adding in components which is what he wanted.
Before you start on any solution though, look at the installation instructions that came with all of your devices (glass breaks, keypads, motion detectors, cameras, etc...) and write down how much current each of them draws (should be listed under "specifications" in the manual/instructions). This way you can better decide on the options below.
I like Elk's external 12 volt power supplies that include an Elk battery backup (much like your M1) plus a forgiving "short circuit" safety feature. Elk offers two versions, a
One Amp Model and a
Four Amp Model.
Now I also like to know that if one of the many, many wires going all over the place (motions, glass breaks, keypads, cameras, etc...) gets shorted, that it will not take down the entire system. Plus, I don't want the wire getting "exposed" to the maximum current draw of the power supply before it "trips".
So I use Elk's
Power Distribution Modules to distribute the 12 volts to each unit. Sometimes I will connect two sensors or so on one of the outputs (i.e. maybe keep all the glass breaks on one output), but the idea is to get the fuseable limit down to something a little more reasonable. In the case of this unit the fused setting is 250 milliamps (1/4 of an amp). In the case where you need higher output capabilities (say for a multiple IR LED camera) you can double the outputs, or use
THIS distribution module which has 400 milliamp fused outputs.
Just listing some options to think about.
Regards,
BSR