Burglar alarms have become standard equipment in stores and other businesses, and they're becoming increasingly common in private homes as well. If you've ever shopped for a home security system, then you know there are a wide variety of options available. These systems range from do-it-yourself kits you can pick up for $10 to sophisticated whole-house security networks that must be installed by professionals. But, as it turns out, most alarm systems are actually built around the same basic design concepts.
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