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Ask HN: How Do Emergency Alerts on Phone Work?
I’m now in UAE which is affected by war. Woke up to an alert yesterday night and was wondering how this works. Any good write ups on its technical side?
- WarOnPrivacy 7mo agoDelivery Method: WEA utilizes a one-to-many alert delivery service called SMS-Cell Broadcast (SMS-CB), rather than SMS Point-to-Point (SMS-PP). SMS-Cell Broadcast (SMS-CB) is a method for sending short text messages simultaneously to multiple mobile phone users within a specific geographic area. It is a feature within the GSM (Global System for Mobile Communications) standard and is sometimes referred to as Cell Broadcast. ref: https://www.etsi.org/deliver/etsi_ts/144000_144099/144012/07.00.00_60/ts_144012v070000p.pdf https://www.etsi.org/deliver/etsi_ts/144000_144099/144012/07...
- rishikeshs 7mo agoIs this a universal standard? How does it override my phone’s volume!
- Jeremy1026 7mo agoTypically there are laws dictating how emergency alerts have to be delivered, and your phone's OS will follow that. So "it" doesn't override your phone's volume. Your phone's OS will override it's volume when it receives the alert.
- david_allison 7mo agoMight as well start with the source code[0] and dig deeper: * CMAS https://en.wikipedia.org/wiki/Wireless_Emergency_Alerts https://en.wikipedia.org/wiki/Wireless_Emergency_Alerts * ETWS Earthquake and Tsunami Warning System [0] https://cs.android.com/android/platform/superproject/main/+/main:packages/apps/CellBroadcastReceiver/src/com/android/cellbroadcastreceiver/CellBroadcastAlertService.java https://cs.android.com/android/platform/superproject/main/+/...