CCTV & Networking Glossary

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Cameras & video↑ Top

IP camera (network camera)

A camera that compresses video itself and sends it over Ethernet or Wi-Fi as an IP stream, instead of the analog signal a coax camera sends to a DVR. Most models take power and data on one cable via PoE. Browse IP cameras →

Bullet / dome / turret

The three fixed-lens housings. Bullet: visible deterrent, long IR reach, easy wall mounting. Dome: vandal-resistant cover, discreet, but the cover can reflect IR. Turret (eyeball): dome-sized ball with no cover, so IR is cleaner and the lens can be re-aimed by hand.

PTZ camera

Pan-Tilt-Zoom: a motorised camera that turns, tilts and zooms optically (25× to 42× on typical models), so one unit covers a yard, a gate or a perimeter. Needs more power than a fixed camera — usually a PoE+ or 802.3bt port, or a separate supply. Browse PTZ cameras →

Varifocal / motorised zoom lens

A lens whose focal length can be changed (e.g. 2.8–12 mm) to trade field of view for detail. Manual varifocal is set once at install; motorised zoom is adjusted remotely from the NVR or app, which saves ladder time on high poles.

Focal length & field of view (2.8 / 4 / 6 mm)

The lens in millimetres decides how wide the camera sees: 2.8 mm ≈ 100° horizontal for a room or car park, 4 mm ≈ 80° for a corridor or driveway, 6 mm ≈ 50° to read a gate 15 m away. Wider is not better — a face needs about 250 pixels across to be identified.

IR night vision (infrared illuminator)

Built-in 850 nm LEDs that light the scene invisibly at night; the image switches to black-and-white. Rated range (30 m, 50 m, 80 m) is the distance at which a person is still recognisable — and the LEDs are the reason a camera draws its peak power after dark.

12 V DC vs PoE power

Most IP cameras accept either a local 12 V DC adapter or PoE on the network cable. PoE wins on every count for installs — one cable, central UPS backup, remote reboot — while 12 V remains useful for Wi-Fi cameras and retrofits where the switch has no PoE.

Full-colour night vision

Cameras with a large-aperture lens, a high-sensitivity sensor and warm white LEDs that keep colour at night (Uniview ColorHunter / LightHunter, Uniarch full-colour). Colour of clothing and vehicles is evidence that IR black-and-white cannot give. Browse full-colour cameras →

WDR (Wide Dynamic Range)

The camera exposes the same frame twice (bright and dark) and merges them, so a face in a doorway is readable against a sunlit street. Quoted in dB: 120 dB true WDR is the entrance-and-lobby standard; 'DWDR' is a software approximation.

Starlight / low-light sensor

A marketing name for sensors that keep a usable colour image down to about 0.001–0.005 lux — a moonlit street — before switching to IR. Look at the lux figure in the datasheet, not the word.

Lux (minimum illumination)

The light level at which the camera still gives a usable picture: 0.01 lux is a street with weak lamps, 0.001 lux moonlight, 0 lux with IR on. Compare cameras at the same aperture (F1.0 vs F1.6) and colour/black-and-white mode, otherwise the numbers mean nothing.

IP66 / IP67 / IK10 ratings

IP (IEC 60529) rates dust and water: IP66 = dust-tight and powerful water jets; IP67 = dust-tight and 30 minutes under 1 m of water. IK10 (IEC 62262) is impact resistance — 20 joules, roughly a 5 kg weight dropped from 40 cm — the vandal-proof grade for domes at hand height.

ONVIF (Profile S / G / T)

The open standard that lets cameras and recorders from different brands work together. Profile S covers live streaming and PTZ control, Profile G recording and playback on the device, Profile T H.265 streaming plus analytics metadata. Ask for the profile, not just the logo.

RTSP stream

Real Time Streaming Protocol — the standard URL (rtsp://user:pass@ip:554/…) by which any VMS, NVR or media player pulls a camera’s live video. If a camera exposes RTSP, it can be recorded by third-party software even without ONVIF.

H.264 / H.265 / H.265+ (Ultra 265)

Video compression standards. H.265 (HEVC) needs roughly half the bitrate of H.264 for the same picture; the vendor 'smart' variants (H.265+, Uniview Ultra 265) cut a further 30–50% on static scenes. Codec choice is the biggest lever on storage and bandwidth.

Bitrate (CBR / VBR)

How many megabits per second a camera stream uses — typically 2–4 Mbps for a 4 MP H.265 camera. CBR holds a fixed rate; VBR lets it fall on quiet scenes and rise on motion, which saves disk. Bitrate × channels × days is what sizes the NVR drives. Size the drives with the storage calculator →

Resolution & frame rate (2 MP / 4 MP / 4K, fps)

Megapixels set how much detail is in each frame (2 MP = 1080p, 4 MP = 2560×1440, 8 MP = 4K); frames per second set how smooth motion is. 4 MP at 15–20 fps is the usual sweet spot for surveillance — more pixels cost more bitrate and more disk, not more evidence.

AI / smart detection (human & vehicle)

On-camera or on-NVR analytics that classify moving objects as people or vehicles and trigger rules such as intrusion, line crossing and enter/leave area. Cuts false alarms from animals, rain and headlights, so a guard actually reacts to the push notification.

Active deterrence (strobe & siren)

A camera with a white strobe, a loudspeaker and two-way audio that reacts to an AI event on the spot — flashing, playing a warning or letting the operator speak. Turns a recorder of incidents into a device that prevents them.

Solar / 4G camera

A battery camera charged by a solar panel that sends video over an LTE SIM instead of a cable — for farms, construction sites, pipelines and gates with no power or network. Sized by panel watts, battery Wh and the number of cloudy days it must survive. Browse solar / 4G cameras →

Wi-Fi camera

A camera that joins the site’s wireless network instead of a cable; many pan-tilt home models. Fine for a shop or house within one or two walls of the router — for anything larger, or where recording must never drop, use PoE. Browse Wi-Fi cameras →

Panoramic / multi-sensor camera

Two to four sensors in one housing stitched into a 180° or 360° view, or paired with a PTZ that zooms into detail (dual-channel and triple-channel models). One pole, one cable, one licence — replaces three or four fixed cameras at a car park or junction.

Thermal camera

Images heat instead of light, so it sees people and vehicles through darkness, fog and smoke at hundreds of metres and is not fooled by headlights or camouflage. Used for perimeters, substations and fire-risk sites; often paired with a visible camera in one unit.

Recording & storage↑ Top

NVR (Network Video Recorder)

The box that records IP camera streams to hard drives and serves live view, playback and remote apps. Sized by channels (4 to 128), incoming bandwidth (Mbps), decoding capacity and drive bays. A DVR does the same for analog coax cameras. Browse NVRs →

PoE NVR

An NVR with built-in PoE ports (4, 8 or 16) that power the cameras directly and auto-add them — the plug-and-play choice for small sites. Beyond 16 cameras, or with long runs, a separate PoE switch is cheaper and easier to expand. Browse PoE NVRs →

AI NVR

A recorder with its own analytics chip that adds face recognition, people counting, vehicle classification and smart search to any connected camera — including older ones with no AI. Search by 'person in red, Tuesday, gate 2' instead of scrubbing hours of video. Browse AI NVRs →

Channels, incoming bandwidth & decoding

Three NVR limits that must all be respected: channel count (how many cameras can be added), incoming bandwidth in Mbps (sum of all camera bitrates it can record), and decoding capacity (how many streams at which resolution it can show live at once). A 16-channel unit rated 64 Mbps records sixteen 4 Mbps cameras — not sixteen 8 MP ones.

Surveillance HDD

Hard drives built for 24/7 writing (Seagate SkyHawk, WD Purple): rated for 180 TB/year workload, multi-drive vibration and firmware that favours steady streaming over retries. A desktop drive in an NVR typically fails within 12–18 months and voids the recorder warranty. Surveillance HDD options →

microSD / TF card (high endurance)

Local storage inside the camera for edge recording when the network or NVR is down. Surveillance-grade cards are rated in P/E cycles (3,000 for MLC-class cards) and wide temperature (−25 to 85 °C); a consumer card wears out in months under continuous writing. Surveillance microSD cards →

RAID / redundant storage

Spreading recordings across several drives so one failure loses no video: RAID 1 mirrors, RAID 5/6 stripe with parity. Available on mid-range and enterprise NVRs with 4+ bays; for a 1- or 2-bay recorder, redundancy means the camera’s SD card plus scheduled backup.

Retention days

How many days of video the drives hold before the oldest is overwritten. 30 days is the common commercial requirement; banks, casinos and some regulators demand 90. Retention = drive capacity ÷ (channels × bitrate × hours per day), which is exactly what the storage calculator does. Open the storage calculator →

Main stream / sub-stream

Every IP camera sends two (sometimes three) streams: the full-resolution main stream for recording and a low-resolution sub-stream (e.g. 640×360) for multi-screen live view and mobile apps. Live view uses the sub-stream so that sixteen cameras fit through a 4G phone connection.

VMS & P2P remote access

VMS (video management software) is the PC/server application that manages many cameras and recorders across sites (Uniview EZStation, brand-neutral options). P2P is the cloud relay (EZView, UNV-Link, Uniarch app) that lets a phone reach the NVR without port forwarding or a fixed IP.

Networking & PoE↑ Top

PoE — 802.3af / at / bt

Power over Ethernet: the switch sends DC power down the same Cat5e/6 cable as the data. 802.3af delivers 15.4 W per port (12.95 W at the camera), 802.3at ‘PoE+’ 30 W (25.5 W), 802.3bt Type 3 60 W and Type 4 90 W. Each is backward-compatible with the classes below it. Browse PoE switches →

PoE budget

The total watts a switch can supply across all its PoE ports at once — separate from the per-port maximum. An 8-port ‘PoE+’ switch with a 60 W budget cannot run eight 25 W cameras. Add 20% headroom for IR, heaters and PTZ motors peaking together on a cold night. Open the PoE budget calculator →

PoE extend mode (250 m)

A DIP switch or per-port setting on Fast Ethernet PoE switches that pushes power and data to 250 m instead of the 100 m Ethernet limit, by dropping the port to 10 Mbps — enough for one or two camera streams. Beyond 250 m, use fibre or a mid-span industrial switch.

PoE watchdog (PD alive)

The switch pings each powered camera; if a camera stops answering (frozen firmware, a common failure in heat), the port is power-cycled automatically and the camera reboots. Saves a truck roll to a pole 40 km away.

Unmanaged vs managed switch

Unmanaged: plug in and it works, no configuration, no visibility — right for up to ~24 cameras on one site. Managed (L2/L2+/L3): VLANs, QoS, ring redundancy, SNMP monitoring and per-port control from a web page or CLI — required once the network carries more than cameras or spans several buildings. Browse managed switches →

VLAN

A virtual LAN splits one physical switch into separate logical networks (IEEE 802.1Q tags), so cameras, office PCs and guest Wi-Fi cannot see each other. Standard practice: put all CCTV on its own VLAN so a camera compromise cannot reach the accounting server.

QoS (Quality of Service)

Switch rules that give video and voice packets priority over bulk data when a link is congested, so recordings do not drop frames while someone downloads a file. Matters on shared uplinks and wireless bridges more than on a dedicated camera switch.

SFP / fibre uplink

A small plug-in module slot on the switch that takes a fibre transceiver (or a copper one). Single-mode fibre reaches 10–20 km, multi-mode ~550 m, both immune to lightning and ground loops — the right way to link buildings, gates and poles beyond 100 m.

Gigabit vs Fast Ethernet

Fast Ethernet ports carry 100 Mbps, gigabit 1,000 Mbps. A 4 MP camera uses 2–4 Mbps, so 100 Mbps access ports are fine for cameras — but the uplink that collects 16 or 24 of them, and every port on the NVR side, should be gigabit.

Ring redundancy (ERPS / RSTP)

Wiring managed switches in a loop so that if one fibre or switch fails, traffic reroutes the other way. ERPS (ITU-T G.8032) recovers in under 50 ms; RSTP (IEEE 802.1w) in a few seconds. Standard on industrial rings around plants, highways and solar farms.

Industrial (DIN-rail) switch

A fanless switch in a metal case rated −40 to 75 °C, with dual 12–57 V DC inputs, DIN-rail mounting and 4–6 kV surge protection, built for roadside cabinets, substations and factories. IEC 61850-3 / IEEE 1613 models add the EMC immunity that power utilities require. Browse industrial switches →

Surge / ESD protection (kV ratings)

How much transient voltage a port survives: ESD (IEC 61000-4-2) e.g. ±6 kV contact / ±8 kV air, EFT (61000-4-4) and surge (61000-4-5) e.g. ±2 kV differential / ±4 kV common mode. In lightning-prone regions this line on the datasheet decides which switch is still alive after the rainy season.

Cat5e / Cat6 cable & the 100 m rule

Ethernet is specified for a 100 m channel (90 m solid-copper cable plus patch leads, ANSI/TIA-568). Cat5e carries gigabit; Cat6 adds margin for PoE heat and future 2.5/10 G. Copper-clad aluminium (CCA) cable heats up under PoE and drops links — insist on pure copper.

Uplink / downlink ports

Downlink (access) ports face the cameras; uplink ports face the NVR or core switch and carry all the traffic combined. A ‘16+2’ PoE switch means 16 PoE downlinks and 2 gigabit uplinks (often one RJ45 and one SFP). Never daisy-chain more than two switches through camera ports.

IGMP snooping (multicast)

When several NVRs or operator screens watch the same cameras, multicast sends one copy of each stream and the switch duplicates it only on ports that asked. IGMP snooping is the switch feature that makes this work instead of flooding every port — needed in control rooms and video walls.

LED & display↑ Top

LED pixel pitch (P0.9 – P10)

The distance in millimetres between LED centres. Smaller pitch = sharper image and higher price: P0.9–P1.5 for control rooms viewed from 2–4 m, P2.5–P4 for lobbies and stages, P6–P10 for outdoor billboards seen from 10 m or more. Rule of thumb: minimum viewing distance in metres ≈ pitch in mm. Browse LED displays →

COB LED (chip-on-board)

Fine-pitch modules where the LED chips are bonded directly to the board and sealed under a resin layer, instead of individual SMD packages. The surface is flat, moisture- and knock-resistant and can be wiped clean — the right choice for touch-distance rooms, and why COB walls carry longer warranties.

Brightness (nits) & refresh rate (Hz)

Nits (cd/m²) is how bright an LED wall or monitor gets: 500–800 for indoor rooms, 1,500+ for shop windows, 5,000+ for outdoor sun. Refresh rate is how many times per second the LEDs redraw; 3,840 Hz keeps the wall flicker-free on phone cameras and broadcast video.

Video wall & controller

Several LED cabinets or LCD panels driven as one canvas by a video processor or decoder that places camera windows, maps and dashboards anywhere on the wall. For CCTV, the NVR/decoder output resolution and the number of simultaneous windows are the numbers to match to the wall.

Trade & project terms↑ Top

BOM / BOQ

Bill of Materials / Bill of Quantities — the itemised list of every camera, switch, recorder, cable and bracket a project needs, with quantities. Send it to us as a spreadsheet or photo of the tender page; our free 48-hour review flags mismatches (PoE budget, channel count, missing SFPs) before you order. Free 48-hour BOM review →

Incoterms (FOB / CIF / DDP)

ICC rules that fix where the seller’s responsibility ends. FOB Shenzhen: we clear export and load the goods on your forwarder’s vessel or truck; freight and insurance are yours. CIF: we also pay freight and insurance to your port. DDP: delivered to your door with duties paid. Most of our project quotations are FOB Shenzhen. Full terms, warranty & RMA →

Freight forwarder

The logistics company that consolidates your goods in China, books the vessel or flight, handles export documents and delivers to your port or door. Most African and Latin American buyers already have one in Guangzhou or Shenzhen; give us their warehouse address and we deliver there under FOB.

Proforma invoice (PI)

The document that turns a quotation into an order: it lists models, quantities, unit prices, Incoterm, lead time, payment terms and bank details, and is what your bank needs to release a T/T. Once you sign or pay against the PI, the models and prices on it are locked.

T/T payment

Telegraphic transfer — a bank wire to the seller’s account in USD, the standard way B2B equipment orders are paid. Typical terms are a deposit on the PI and the balance before shipment; the lead time clock starts when the deposit lands.

Lead time

Days from payment to goods at your forwarder’s China warehouse: 3 days for models in stock, 7–15 working days when a batch must be produced. Then add transit — 5–10 days by air, 25–45 days by sea to African and Latin American ports.

Sample order

A small first order — one or a few units — to test the product on your bench or a pilot site before committing to volume. Welcome on every model; samples ship by courier and are quoted at the same project pricing logic, not a retail markup.

MOQ (minimum order quantity)

The smallest quantity a supplier will sell. Standard models on this site have no MOQ — one unit ships as a sample order — while custom firmware, private labels or special colours need a production batch (typically 50–100 units).

CE / FCC / RoHS

Compliance marks customs and tenders ask for: CE (EU safety and EMC directives), FCC (US radio-frequency emissions) and RoHS (restriction of hazardous substances such as lead and cadmium). Our industrial switches carry all three; certificates are supplied with the PI on request.

Warranty & RMA

RMA (Return Merchandise Authorisation) is the process for a defective unit under warranty. Because cross-border shipping of one camera costs more than the camera, our B2B terms replace returns with free spare units agreed per order and written into the quotation — you keep the failed unit for your own records or repair. Warranty & RMA terms →

Questions installers ask

Short answers you can quote to your own customers.

References

Standards behind the definitions. Product figures (PoE budgets, channel counts, IP ratings) come from the datasheets on each model page.

1. IEEE 802.3-2022 — Ethernet, incl. Power over Ethernet (Clauses 33 / 145)
2. ONVIF — Profiles S, G and T
3. IEC 60529 — Degrees of protection provided by enclosures (IP Code)
4. IEC 62262 — Degrees of protection against external mechanical impacts (IK Code)
5. ITU-T G.8032 — Ethernet ring protection switching (ERPS)
6. ICC — Incoterms® 2020 rules
7. ITU-T H.265 — High efficiency video coding