Linkage integration of video surveillance, access control, and alarm systems: interface methods and implementation points
Why linkage is needed
Single video surveillance can only "verify afterwards", but only after access control and alarm are connected, the system can have the ability to "respond during the event": automatic capture and comparison when the access control card is swiped, automatic pop-up screen and start recording when the detector alarms, When the fire signal is triggered, the linkage channel is unlocked and the live video is pushed. This is also the main value of security system integration.
Four interface modes
| Methods | Practice | Advantages | Limitations |
|---|---|---|---|
| Dry contact (relay) | The alarm host outputs a switching value and is connected to the alarm input of the camera or NVR | Simple and reliable, no protocol dependency | Only status can be transmitted, but details cannot be transmitted |
| SDK / API | The platform calls the development interface of the equipment manufacturer | The most complete function and two-way interaction | Dependent on the manufacturer, high cross-brand costs |
| Standard protocol | ONVIF event, GB/T 28181 alarm notification | Common across brands | Each manufacturer has different levels of implementation |
| Platform-level integration | Each subsystem is connected to the unified management platform | Unified configuration and unified permissions | The platform needs to have corresponding access capabilities |
Typical linkage process design
- Access card swiping capture: Card swiping event → The platform calls the corresponding camera to capture → Compare with face database or registration photo → Alert when abnormal. The key is the correspondence between events and cameras, It is necessary to clarify "which access control corresponds to which camera" in the point table.
- Intrusion alarm pop-up image: The detector is triggered → the platform pops up a preset associated screen → Automatically start recording and mark → notify the person on duty. Please pay attention to the limit on the number of pop-ups. When multiple detectors are triggered at the same time, they should be queued according to priority instead of popping them all.
- Firefighting linkage: The firefighting signal has the highest priority. When triggered, the linkage channel is unlocked. The camera switches to the preset position and the recording is marked as non-overwriteable. Fire linkage usually requires hard wiring, You cannot rely solely on network transmission.
Common reasons for failure of joint debugging
- Event not received: Most of the dry contact wiring errors (normally open/normally closed reverse connection), The second is that the alarm input is not enabled on this channel.
- Event received but no linkage: The linkage rule is not configured, or the camera number referenced in the rule is incorrect.
- Large linkage delay: The platform polling cycle is too long, or the event volume is too large, causing queue backlog.
- The test is normal but the actual operation fails: The test uses a single event. In actual combat, multiple events concurrently triggered unexpected rule conflicts.
Key points for acceptance
The linkage function must be measured one by one and kept records: each detector triggers once, Every time the access control card is swiped, the four steps of confirming that the screenshot, video, pop-up window, and notification are all effective. It is not enough to verify that "the platform shows an event".
