[Duplicate alarm signals]

Thanks for your replies.   We handle intruder and fire alarms for over 5,000+ premises UK-wide including a large retail chain with over 400+ stores and it's the retail stores that I have the confusion with.    We don't get duplicates on every activation from every store but I have known to receive a single activation, followed by several duplicates and finally a verified which was later confirmed as a break-in, and we've also had a single followed by duplicates and that also was a confirmed as a break.   So my question really is, are the duplicates an indication that a break-in is taking place without receiving a verified signal?   The stores are using webway.

[Duplicate alarm signals]

I have recently started working in an ARC with no previous experience.    Although I'm learning very fast, I'm stuck on one thing which no-one can provide an answer to that I understand.    When we receive a single activation, we sometimes then receive a 'duplicate'.   Does anyone know what this duplicate means, and whether this should be policed although I'm told the duplicate is not a verified signal?