Reference hub
The WhatCableWorks glossary explains the cable, port, adapter, charging, and display terms that confuse people most. Use it when a product page, spec sheet, or troubleshooting guide throws technical language at you and you want the simple version before you buy the wrong thing.
This glossary helps you decode terms like USB-C, DisplayPort, Alt Mode, active adapter, passive adapter, ARC, eARC, and Thunderbolt in plain English. Start here when you want to understand what a term means, why it matters, and what mistake people usually make with it.
- You want simple definitions before buying a cable or adapter
- You are not sure what a port or feature actually does
- You want to understand why a setup works or fails
- You need one reference page that links to deeper guides
- A full compatibility article for a specific device pair
- A direction-specific converter guide
- A model-by-model port support check
- A full troubleshooting guide for one exact setup
Jump to a term
Core terms most people actually need
USB-C
What it is USB-C is the small oval connector used on many modern phones, tablets, laptops, docks, chargers, and monitors.
Why it matters A USB-C port can support charging, data, and sometimes video, but not every USB-C port supports all of those functions.
Common mistake People often assume every USB-C port can connect to a monitor. That is one of the most common wrong assumptions on this site.
DisplayPort
What it is DisplayPort is a digital audio and video connection used mostly on PCs, monitors, graphics cards, and docking setups.
Simple history It was developed as a modern PC-focused display standard built for higher display performance and flexible monitor setups.
Where you see it Desktop monitors, business laptops, gaming PCs, docking stations, and some USB-C video paths.
Why it matters DisplayPort is common in high-refresh-rate monitor setups, multi-monitor setups, and USB-C video output through DisplayPort Alt Mode.
Common mistake People assume DisplayPort and HDMI are always interchangeable. They are not. Direction and signal support still matter.
HDMI
What it is HDMI is the most common digital connection for TVs, soundbars, AV receivers, streaming devices, projectors, game consoles, and many monitors.
Simple history HDMI was created to carry digital video and audio together over one cable and simplify home AV connections.
Where you see it TVs, projectors, streaming sticks, sound systems, consoles, and many laptops.
Why it matters HDMI is the connection most home users deal with, but port support, cable quality, and adapter direction still decide what works.
Common mistake People buy a cable based only on a version number and ignore the real limits of the source device, display, and adapter path.
DisplayPort Alt Mode
What it is DisplayPort Alt Mode lets a supported USB-C port carry DisplayPort video through the USB-C connector.
Why it matters This is one of the main reasons USB-C to HDMI and USB-C to DisplayPort products work in many laptop and phone setups.
Common mistake A USB-C port can charge a device and still fail to output video if it does not support DisplayPort Alt Mode or another video mode.
Thunderbolt
What it is Thunderbolt is a high-performance connection standard that uses the same USB-C-shaped connector on many modern devices.
Why it matters Thunderbolt usually offers stronger baseline support for docks, displays, fast storage, and combined data-plus-video setups than generic USB-C alone.
Common mistake People confuse the connector shape with the capability. A USB-C-shaped port is not automatically Thunderbolt.
USB Power Delivery
What it is USB Power Delivery, often written as USB PD, is the charging standard that lets compatible USB-C devices negotiate higher power levels.
Why it matters It affects whether a cable or charger can correctly power a phone, tablet, laptop, dock, or monitor.
Common mistake Fast charging is not guaranteed just because the cable has USB-C ends.
Adapter and conversion terms
Active adapter
What it is An active adapter contains electronics that convert one signal type into another.
Why it matters You often need an active adapter when the source and display do not speak the same signal language.
Example HDMI to DisplayPort usually needs active conversion.
Passive adapter
What it is A passive adapter changes the connector form without fully converting the signal.
Why it matters Passive adapters only work when the source already supports the needed signal or connector behavior.
Common mistake People buy a cheap passive adapter and expect it to do full signal conversion. Most of the time, it will not.
Active HDMI cable
What it is An active HDMI cable has electronics built into the cable itself.
Why it matters Active HDMI cables are usually used for longer runs or demanding signal situations where a simple passive cable may not be enough.
Common mistake “Active HDMI” does not mean the same thing as an HDMI-to-something-else active converter.
HDMI passive adapter
What it is A passive HDMI adapter usually changes connector form, such as standard HDMI to Mini HDMI or Micro HDMI, without converting the signal into a different system.
Why it matters It is for physical compatibility, not for turning HDMI into DisplayPort, VGA, or another signal format.
Converter
What it is A converter is a device that changes one signal format into another.
Why it matters If the source and display use different signal types, you usually need a converter, not a simple adapter.
Common mistake Adapter and converter are often used as if they mean the same thing. They do not.
Directionality
What it is Directionality means a cable or adapter only works in one signal direction.
Why it matters HDMI to DisplayPort and DisplayPort to HDMI are not automatically the same thing, even if the connector names are the same words reversed.
Common mistake People buy the reverse-direction product and think the product is defective when it fails.
DP++
What it is DP++ means Dual-Mode DisplayPort.
Why it matters It allows some DisplayPort outputs to send an HDMI- or DVI-compatible signal through the right passive adapter.
Common mistake People assume every DisplayPort source supports DP++. Not all do.
Display and signal features
MST
What it is MST stands for Multi-Stream Transport.
Why it matters It allows one DisplayPort connection to carry multiple display streams in supported setups, which is why some docks and daisy-chain monitor setups can run more than one screen from one source connection.
DSC
What it is DSC stands for Display Stream Compression.
Why it matters It helps some high-resolution and high-refresh-rate setups fit within real bandwidth limits while maintaining very high visual quality.
HDCP
What it is HDCP is copy protection used on many digital video connections.
Why it matters If one device in the chain does not support the required HDCP level, protected content may fail, downgrade, or show a black screen.
ARC
What it is ARC stands for Audio Return Channel.
Why it matters It lets a TV send audio back to a soundbar or AV receiver through an HDMI cable, so you do not always need a separate audio cable.
Common mistake People connect to a normal HDMI port instead of the ARC-labeled port and then wonder why the sound system does not receive TV audio.
eARC
What it is eARC is the enhanced version of ARC.
Why it matters It supports higher-quality audio and is better for newer home theater setups.
Common mistake People assume ARC and eARC are the same thing. They are related, but eARC is the more capable version.
Everyday hardware terms
Dock
What it is A dock is a connection station that expands one laptop port into several outputs such as video, USB, Ethernet, audio, and charging.
Why it matters A dock can simplify a desk setup, but it still depends on what the laptop port actually supports.
Hub
What it is A hub is a smaller expansion device that adds extra ports to one USB-C or USB-A connection.
Why it matters Hubs vary a lot in power, data speed, and video support. Two hubs that look similar may behave very differently.
Full-featured USB-C cable
What it is A full-featured USB-C cable is built to support more than simple charging alone.
Why it matters In many setups, the cable is the hidden reason video, fast charging, or higher-speed data does not work.
Charge-only cable
What it is A charge-only cable can provide power but may not support fast data or video functions.
Why it matters This is a common reason a USB-C device charges but will not connect to a monitor or data accessory.
Display quality terms
Resolution
What it is Resolution is the number of pixels on the screen, such as 1920×1080 or 3840×2160.
Why it matters Higher resolution can look sharper, but it also demands more from the source device, port, cable, adapter, and display.
Refresh rate
What it is Refresh rate is how many times the screen updates each second, such as 60Hz, 120Hz, or 144Hz.
Why it matters A setup that can do 4K at 30Hz is not the same as one that can do 4K at 60Hz or higher.
HDR
What it is HDR stands for High Dynamic Range.
Why it matters HDR can improve contrast and color, but it depends on support from the source device, display, connection path, and content.
Legacy and older connector terms
VGA
What it is VGA is an older analog video connection.
Why it matters VGA often needs active conversion when connecting to newer digital ports like HDMI, USB-C, or DisplayPort.
Common mistake People expect a simple passive cable to convert VGA to HDMI or HDMI to VGA in every direction. That usually fails.
DVI
What it is DVI is an older display connection that exists in several forms, including digital and analog variants.
Why it matters Whether a DVI setup works depends on the exact DVI type and the direction of the conversion path.
Mini DisplayPort
What it is Mini DisplayPort is a smaller version of the DisplayPort connector.
Why it matters It still carries DisplayPort, but it needs the right physical cable or adapter.
Mini HDMI
What it is Mini HDMI is a smaller HDMI connector used on some cameras and compact devices.
Why it matters It is still HDMI in signal terms. The connector is just smaller.
Micro HDMI
What it is Micro HDMI is an even smaller HDMI connector used on some very compact devices.
Why it matters It still carries HDMI signal, but you need the correct cable or passive connector adapter for the smaller port.
Lightning
What it is Lightning is Apple’s older connector used on many iPhones and iPads before USB-C became more common.
Why it matters Lightning video output uses Apple-specific accessories and is not the same as normal USB-C display output behavior.
Micro USB
What it is Micro USB is an older small USB connector used on many older phones, accessories, and budget devices.
Why it matters Most Micro USB ports do not output video. Older exceptions often depended on special support like MHL.
MHL
What it is MHL stands for Mobile High-Definition Link.
Why it matters It was one of the older ways some phones could output video through Micro USB, but support was never universal and is much less common on newer devices.
Bottom line
Use this glossary to decode confusing terms fast, then check the full guide for your exact setup before buying a cable or adapter. The connector may fit, but that does not always mean the signal will work.