An alarm normally has an internal battery, but cameras, switches, routers and recorders can fail separately. Internet loss need not stop local recording. Continuity requires power, local networking, secondary communication, storage and fault supervision.
Key points
- Map power and communication.
- Separate local operation from remote access.
- Size backup for real load.
- Test outage and recovery.
Several links
Alarm, modem, PoE switch, recorder and access controller each have dependencies.
The weakest backup duration limits the complete service.
- Panel
- Sensors
- PoE
- Router
- NVR
- Access
Power loss
Battery capacity falls with age and temperature; test at full load.
A UPS can support network and video without unnecessary loads.
- Capacity
- Age
- Load
- UPS
- Mains alert
Internet loss
Local detection and recording may continue while apps and cloud stop.
A cellular path may send events; check which data it carries.
| Failure | May remain | Affected | Measure |
|---|---|---|---|
| Internet | Local systems | App/cloud | Cellular |
| Power | Battery/UPS | Other loads | Size |
| Switch | Edge | NVR path | UPS/edge |
| NVR | Live | History | Edge/cloud |
| Cellular | Fixed line | Backup | Supervision |
Storage layers
NVR records locally; edge storage bridges network loss; cloud protects off-site.
Document primary source, synchronisation and gaps.
- NVR
- Edge
- Cloud
- Sync
- Gap alert
Access and doors
Keep necessary rights locally and define each door during power loss.
Exit doors, barriers and secure rooms have different needs.
- Local rights
- Battery
- Evacuation
- Mechanical release
- Log
Report faults
Separate mains, battery, connection, camera and disk faults.
Assign priority, recipient and escalation.
- Type
- Priority
- Recipient
- Escalation
- Closure
Continuity testing
Safely test internet loss, power loss, autonomy and recovery.
Repeat after network or system changes.
- Internet
- Power
- Runtime
- Recovery
- Report
FAQ
Will an alarm work without power?
For a limited time with a healthy charged battery.
Can cameras record without internet?
Yes with local power and storage.
Does 4G replace all internet?
It may carry selected signals depending on service and bandwidth.
How is runtime known?
Calculate it and perform a supervised test.
