Plain-English definitions of every word you’ll hear us use. One or two sentences each. No prior knowledge assumed.
Adopt / Adoption
The act of a new device joining your system and coming under the controller’s management. Out of the box a UniFi device is a stranger; once adopted, it appears in your app, takes your settings, and gets updates.
Access (UniFi Access)
Ubiquiti’s door-entry system — card readers, door hubs, and electric locks, managed from the same app as everything else. See Door Access.
AFC (Automated Frequency Coordination)
A system that lets outdoor Wi-Fi use the 6 GHz band at higher power. Before it transmits, the access point checks an online database of licensed users already on those frequencies nearby and only uses the channels that are genuinely free, so it doesn’t tread on them.
AHJ (Authority Having Jurisdiction)
The local official or body — usually a building or fire authority — who has the final say on whether an installation is acceptable where you are. The term comes up around doors and exits because their decision, not ours, is the one that counts. AVNFi does not give code or legal advice.
CMR (Conventional Magnetic Recording)
A way of laying data down on a hard drive that handles constant writing well. Cameras write continuously, so surveillance drives are CMR. The cheaper alternative (SMR) overlaps its data tracks and bogs down badly under constant writing. For cameras, insist on CMR.
Controller
The software that manages everything — the place your settings live and where you log in. In UniFi it usually runs inside the gateway, which is why the gateway is called the brain.
DIN rail
A standard 35 mm metal mounting strip (TS35 / EN 60715) found inside electrical panels and control cabinets. Gear designed for it clips straight onto the rail instead of being screwed down, which makes it quick to add or swap. It is named after the German standards body that defined it. Note: no UniFi gateway is DIN-rail mountable, including the UCG-Industrial — that one mounts on a wall, sits on its included table stand, or racks with a separate accessory.
Fail-secure / fail-safe
Two opposite behaviours for an electric door lock when the power goes out. Fail-secure stays locked. Fail-safe unlocks. They are often the same product with a dropdown choice at the point of order, which makes this an easy and expensive thing to get wrong. Which behaviour a given door needs depends on the door, the building and the local authority. See Door Access.
FOV (Field of View)
How wide a camera sees, measured in degrees. A 110° camera takes in a wide room; a 180° camera takes in a whole wall. Ubiquiti publishes field of view in degrees rather than lens focal length in millimetres, and for deciding where a camera goes, degrees is the more useful number.
Gateway
The brain. Router + firewall + controller in one box, and on some models the video recorder as well. Your internet comes in here. See Choosing a Gateway.
Home-run
A cabling method where every cable runs its own uninterrupted path from the device back to one central spot, with nothing daisy-chained in between. It costs more cable and it’s worth it — one bad cable takes down one device, not a chain of them.
IK rating
How hard you can hit something before it breaks. IK04 survives a modest knock; IK10 is the top of the scale and is what “vandal-resistant” actually means. Relevant for cameras within reach of the public.
IP rating (Ingress Protection)
How well a device keeps out dust and water. Two digits: the first is dust, the second is water. IP66 — fully dust-tight and stands up to powerful water jets — is the common outdoor camera rating. IPX4 or IPX5 means only splash or spray resistance: indoor or sheltered use.
IR (Infrared)
Invisible light a camera shines to see in complete darkness. Video goes black-and-white when IR is on. Ubiquiti publishes an IR range in metres — how far the camera can usefully see with no other light at all.
Keystone
The small snap-in socket that a network cable terminates into at a wall plate or patch panel. It’s the standard connector shape that makes the whole tidy, serviceable system possible.
Layer 2 / Layer 3
Two levels a switch can work at. Layer 2 simply moves traffic between devices on the same network — that is all most switches ever need to do. Layer 3 can also route traffic between separate networks on its own, taking that work off the gateway. Larger sites use Layer 3; a home never needs it.
microSD
The same small memory card a phone or camera uses, showing up here as a little built-in storage. The UCG-Industrial, for example, ships with a pre-installed 128 GB card that it records to. It holds a tiny fraction of what a real surveillance drive does, so treat it as small or backup recording — not weeks of footage.
MLO (Multi-Link Operation)
A Wi-Fi 7 feature that lets a device use more than one band at the same time — say 5 GHz and 6 GHz together — instead of committing to just one. The result is a faster, steadier connection. Both ends have to be Wi-Fi 7 for it to happen.
NDAA
A piece of US legislation whose surveillance provisions some organisations must buy against. Ubiquiti publishes NDAA information in each product’s technical specifications rather than as a single list. If NDAA status matters for your project, get it in writing from Ubiquiti for your exact model list — don’t take it from a retailer badge or from us.
NVMe
A type of small, very fast solid-state drive that plugs straight onto a circuit board rather than sitting in a drive bay. Some gateways record camera footage onto one instead of a hard drive. It is quick, but the capacity is limited next to a proper surveillance drive — see Storage and Retention.
NVR (Network Video Recorder)
The box with hard drives that stores your camera video. Some gateways have one built in; otherwise it’s a separate unit.
Patch panel
A row of sockets in the rack where all the cables from around the building land. From there, short cables jump across to the switch. It exists so nobody ever has to touch the cable in the wall again.
PoE (Power over Ethernet)
Power and data down one network cable, so a camera or access point needs no power outlet. The base standard is 802.3af, delivering up to 15.4W per port. See Switches and PoE.
PoE+
The next tier up (802.3at). Roughly 30–32W per port depending on the switch. Needed by higher-draw cameras and most Wi-Fi 7 access points.
PoE++
Higher again (802.3bt), up to 64W per port on UniFi switches. Needed by door hubs, multi-sensor cameras and the biggest access points.
PoE+++
Ubiquiti’s label for its highest-power tier, above PoE++, found on some of its 10G ports and XG-series switches. Ubiquiti doesn’t publish a per-port wattage for it in the data we hold, so we don’t quote one.
Protect (UniFi Protect)
Ubiquiti’s camera system — cameras, doorbells, and the recording. Records locally, no subscription. See Choosing Cameras.
RU / rack unit
The height measurement for rack-mounted equipment. 1U is one rack unit — about 44 mm, or 1.75 inches. A “1U” gateway takes up one slot; a 12U cabinet has room for twelve. It is how you work out whether a box will physically fit before you buy it.
SFP / SFP+ / SFP28 / QSFP28
A family of slots that take a small plug-in module, usually for fibre optic cable instead of the familiar square Ethernet socket. The names are really just speeds: SFP is 1 Gbps, SFP+ is 10, SFP28 is 25, and QSFP28 is 100. If your internet arrives on fibre, this is the sort of port it plugs into.
SMR (Shingled Magnetic Recording)
The cheaper way of writing data to a hard drive — the tracks overlap like roof shingles to squeeze more in. It is fine for files you rarely change and poor at constant writing, which is exactly what cameras do all day. Never put an SMR drive in a recorder. See CMR.
SSID
The name of a Wi-Fi network — the thing you tap on your phone. One access point can broadcast several, which is how a guest network exists alongside your main one.
STR (Simultaneous Transmit and Receive)
The strongest form of MLO. The device can send on one band while receiving on another at the same moment, rather than taking turns. When a spec sheet says “STR MLO”, it means the multi-link feature is the full-strength version.
Uplink
The cable connecting one network box to another — a switch back to the gateway, say. It’s the road everything else’s traffic drives down, so it’s usually the fastest port on the box. When counting ports, always count the uplink; it uses one.
VLAN (Virtual LAN)
A way of splitting one physical network into several separate ones that can’t see each other, without running any more cable. In practice: your cameras live on their own network, guests on theirs, and your laptop on yours — one set of wires, three sealed-off worlds. Useful because a compromised device can only reach its own neighbourhood.
Missing a word? Tell AVNFi and we’ll add it.