By the SightShield team · · 3 min read
Why a glossary helps
CCTV quotes and data sheets are full of abbreviations. Understanding them lets you compare quotes properly and ask the right questions. Here are the terms you are most likely to meet, explained simply, with links to our detailed guides.
Cameras and recorders
| Term | Meaning |
|---|---|
| IP camera | A network camera that sends digital video over an Ethernet cable or Wi-Fi |
| Analog / HD camera | An older type sending video over coaxial cable to a DVR |
| NVR | Network video recorder — records IP cameras |
| DVR | Digital video recorder — records analog/HD cameras |
| Channel | One camera input on a recorder |
| Dome, bullet, turret | Camera body shapes |
| PTZ | Pan-tilt-zoom camera that can be moved and zoomed remotely |
| Fisheye | A 360-degree camera that sees a whole room from the ceiling |
Image and video terms
| Term | Meaning |
|---|---|
| MP (megapixel) | Resolution — 2MP is 1080p, 4MP is about 2560×1440, 8MP is 4K |
| FPS | Frames per second — 15 to 25 is typical for CCTV |
| Bitrate | Amount of data per second the camera sends, in Mbps — decides storage |
| H.264 / H.265 | Video compression standards; H.265 needs less storage for similar quality |
| Main stream / sub-stream | High quality stream for recording; lower quality for phone and grid views |
| Lens (mm) | Focal length — smaller mm sees wider, larger mm sees farther |
| Varifocal | A lens whose zoom can be adjusted during installation |
| WDR | Wide dynamic range — handles bright backgrounds like glass doors |
| IR | Infrared lights for black-and-white night vision |
| Colour night vision | Sensors and lenses that give colour images in low light |
Network and power terms
| Term | Meaning |
|---|---|
| PoE | Power over Ethernet — one cable carries power and data to the camera |
| PoE switch | A network switch that powers cameras through their cables |
| Cat6 | The standard copper network cable for IP cameras, up to 100 metres |
| VLAN | A separate virtual network to keep cameras apart from other devices |
| P2P / cloud service | The maker’s service that lets apps reach your NVR without opening router ports |
| ONVIF | An open standard that lets cameras and recorders from different brands work together |
| UPS | Battery backup that keeps the NVR, switch and router running in power cuts |
Durability and certification
| Term | Meaning |
|---|---|
| IP66 / IP67 | Dust and water protection ratings for outdoor cameras |
| IK10 | Impact resistance rating for vandal-proof domes |
| STQC / BIS registration | India’s security testing and registration that network cameras need before sale |
| Surveillance hard disk | A disk designed for continuous 24-hour recording |
Smart features
| Term | Meaning |
|---|---|
| Motion detection | Triggers on any change in the picture |
| Human/vehicle detection | AI that alerts only for people and vehicles |
| Line crossing | Alarm when a person or vehicle crosses a virtual line |
| ANPR / LPR | Automatic number plate recognition |
| Face recognition | Identifying enrolled people by face |
| Active deterrence | Cameras with strobes, sirens or voice warnings |
| VMS | Video management software to manage many cameras and recorders |
| Retention | How many days of footage are kept before overwriting |
Recording and evidence terms
| Term | Meaning |
|---|---|
| Continuous recording | Recording all the time, regardless of activity |
| Event recording | Recording or marking footage only when motion or an alarm occurs |
| Overwrite | When the disk is full, the oldest footage is replaced by new footage |
| RAID | Disk arrangement that keeps recordings safe if one disk fails |
| Export / backup | Copying a clip from the recorder to a USB drive, phone or computer |
| Watermark | Hidden data that helps show a clip has not been altered |
| NTP / time sync | Automatic clock setting so recordings carry the correct date and time |
Still confused by a quote?
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Contact SightShield →Quick answers
What is the difference between NVR and DVR?+
An NVR records IP cameras over a network; a DVR records analog/HD cameras over coaxial cable.
What does PoE mean in CCTV?+
Power over Ethernet: one network cable carries both power and video to the camera.
What does 2.8 mm or 4 mm lens mean?+
The focal length. Smaller numbers see wider; larger numbers see farther with a narrower view.
What is ONVIF?+
An open standard that lets cameras and recorders from different brands work together.