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Who still uses pagers?
(www.voanews.com)
This is a most excellent place for technology news and articles.
Opsgenie and PagerDuty let you add them as contacts from within the app and it manages the rotating numbers for you so you can keep using a specific ringtone for them. This is also how they can override DND so you can go back to muting your phone at night and know that pages will still come in.