The CARES alarms are portable boxes with HT's (on the 800 system as you noted) and motion detectors in them that transmit a message to dispatch when they are tripped. They can be used to catch criminals in places that they are anticipated to hit. An example could be a radio tower site. If there had been a lot of recent copper theft activity (as there is) at radio sites, the police may set several of these things out at other towers and when they trip the police respond to try to catch the thief. I don't know if they have ever caught anyone with one of these, but it seems like a good tool to have. The PD has had them for years. I don't know how often they actually deploy them.