Tech glossary
Spec sheets are full of acronyms. Here is what each one means, in plain English and straight to the point, so you can compare products knowing what you are reading.
Water and dust resistance
What is an IP rating?
An IP rating (Ingress Protection) is a code from the international standard IEC 60529 that states how well a device resists dust and water. It has two digits: the first, from 0 to 6, covers solids; the second, from 0 to 8, covers liquids. The higher the number, the more protection.
What does IP54 mean?
IP54 means the device is protected against dust (5) and against water splashes from any direction (4). It handles rain, sweat and everyday dust. It is not submersible: it does not resist immersion or pressurized water jets.
What does IPX4 mean?
IPX4 means the device resists water splashes from any direction. The X indicates that dust protection was not certified, not that there is none. It is fine for sweat and rain; it is not meant to be submerged or held under running water.
What does IP65 mean?
IP65 means the device is completely dust tight (6) and resists water jets from any direction (5). It is the typical level for outdoor cameras and lights: it handles heavy rain and a garden hose, but it is not designed to be submerged.
What does IP67 mean?
IP67 means the device is dust tight (6) and withstands immersion in water up to 1 meter deep for 30 minutes (7). It survives a fall into water or a rinse. The test is done with fresh water at rest.
What does IP68 mean?
IP68 means the device is dust tight (6) and resists continuous immersion beyond 1 meter deep (8). The exact depth and time are defined by each manufacturer, so two IP68 devices can withstand different things.
What does 5 ATM mean on a watch?
5 ATM means the watch withstands a pressure equal to a 50-meter column of water, measured at rest. In practice it is suitable for rain, a cold shower and surface swimming. It is not suitable for diving or for high-impact water sports.
Projectors
What are ANSI lumens?
ANSI lumens measure the real brightness a projector puts on the screen, using a standard method: light is measured at nine points of the image and averaged. It is the only brightness figure that lets you compare projectors from different brands on equal terms.
What is a projector's native resolution?
Native resolution is the real number of pixels the projector can display. Supported resolution is the highest signal it accepts through its input. A projector that is "1080p native and supports 4K" takes in 4K video but shows it in 1080p.
What is keystone correction?
Keystone correction straightens the image when the projector is not perfectly square to the wall. Without it, the picture comes out shaped like a trapezoid: wider on one side. It can be manual or automatic, when the projector detects its own tilt and adjusts by itself.
Battery and charging
What does mAh mean on a battery?
mAh stands for milliampere-hours and measures a battery's capacity: how much electrical charge it can store. More mAh means more runtime, as long as you compare devices with similar power draw. It does not measure power or charging speed.
What is Power Delivery (PD) fast charging?
Power Delivery (PD) is the fast-charging standard over USB-C. It lets the charger and the device negotiate how much power to use, instead of always delivering the same amount. For it to work, the charger, the cable and the device must all be compatible: if one is not, it charges at normal speed.
Connectivity
What is Bluetooth 5 and how do its versions differ?
Bluetooth 5 is the current generation of short-range wireless connection. Compared with Bluetooth 4 it improved range, speed and power consumption. Versions 5.2 and 5.3 add efficiency and stability improvements. To benefit from them, both connected devices must support that version.
What is the difference between 2.4 GHz and 5 GHz WiFi?
A 2.4 GHz WiFi network reaches farther and gets through walls better, but it is slower and suffers more interference. A 5 GHz network is faster but has less range. Many smart home devices, such as cameras and locks, only connect to 2.4 GHz.
Audio
What is latency in earbuds and controllers?
Latency is the delay between something happening and you perceiving it: between a shot on screen and its sound, or between pressing a button and the response. It is measured in milliseconds (ms). The lower, the better. On Bluetooth earbuds it matters for gaming and for watching video.
What is the difference between ANC and ENC?
ANC (active noise cancellation) reduces the ambient noise you hear, using microphones that pick up outside sound and generate an opposite signal. ENC (environmental noise cancellation) cleans up your voice on calls, so the other person hears you better. One is for you; the other is for whoever is listening to you.
Displays
Health sensors
Security cameras
How does night vision work on a security camera?
Infrared night vision lights the scene with LEDs the human eye cannot see, and the camera records in black and white. Color night vision uses a visible spotlight or a more sensitive sensor to keep colors. The first is discreet; the second gives more detail.
What is two-way audio on a camera?
Two-way audio means the camera has both a microphone and a speaker: from the phone app you can hear what is happening and talk through it. It is useful for answering whoever is at the door, speaking to your pet or warning off an intruder.