The IDS will become a backup system, rarely forced to sound an alarm that someone has actually gotten past your secure threshold.

而IDS则成为了一个备份系统，因为很少人能入侵系统而激活报警机制。

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Alarms that use the analog network as a main or backup link may lose their connection to alarm centers.

警告显示，模拟网络作为主要的或是后备链接，可能会丢失他们与报警中心的联系。

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Monday morning around 5 am I was awoken by the scream of a carbon monoxide alarm in my centralized alarm system, letting me know the battery backup was failing.

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