The big divide: analog and digital
The most useful way to sort video ports is by what kind of signal they carry.
Analog connectors send the picture as varying voltages. VGA is the best-known example, with its blue, trapezoid-shaped plug and small screws. It was designed in an era of monitors built around cathode ray tubes, and it has no built-in way to carry audio. Quality depends heavily on the cable and on the circuits at each end, and a long or poor cable can show softness, ghosting or faint noise.
Digital connectors send the picture as numbers. The display receives exact values for each pixel, so noise on the cable does not blur the image, provided the link still works. Digital links also carry identifying information, so a source can learn what the display supports.
Between the two sits DVI, which was the transition connector. Depending on the variant, a DVI port may carry digital video, analog video or both, and the pin layout of the plug shows which. It does not carry sound.
The common digital families
HDMI. Found on televisions, set-top boxes, game consoles, projectors and many monitors and laptops. It carries video and audio over one cable and includes control features that let devices talk to each other, such as switching inputs. It comes in several versions with different capabilities, and a port’s version determines the highest resolution, refresh rate and extra features it handles. Plug shapes come in full, mini and micro sizes.
DisplayPort. Common on computer monitors and graphics hardware. It also carries video and audio, and it is typically used for high refresh rate and high-resolution monitors. Some versions can route several displays from a single port, and many have a latching plug that clicks into place. Like HDMI, it has versions with different limits.
USB-C. This is a connector shape rather than a video standard. A USB-C port might carry no video at all, or it might carry a DisplayPort-style signal, and the same cable can sometimes also deliver power and carry data. Whether it works depends on the device, the cable and the display all supporting it, so a USB-C port on a laptop does not guarantee video output. Look for a display symbol or the device’s documentation.
Thunderbolt-style ports. These use the same connector shape as USB-C but add high-speed data and video capabilities. They are typically found on higher-end laptops and docks and can often drive displays along with other peripherals.
Where each is typically used
| Situation | Often found |
|---|---|
| Television, console, streaming box | HDMI |
| Desktop computer monitor | DisplayPort or HDMI |
| Thin laptop | USB-C, sometimes HDMI |
| Older office equipment, projectors | VGA, DVI or HDMI |
| Docking stations | USB-C or Thunderbolt-style |
This is a tendency, not a rule. Check the actual ports on your equipment.
Adapters and converters
Adapters are where many setups go wrong, so it helps to understand what they do.
A passive adapter only rearranges pins. It works only when both ends already speak the same signal. A cable with a different plug on each end, say a USB-C to DisplayPort cable, usually relies on the source already outputting a compatible signal.
An active converter contains electronics that change one signal type to another. Going from a digital source to an analog display requires one, as does going the other way. These need power, which may come from the connection or from a separate adapter, and they can limit the maximum resolution or refresh rate.
Some common limits:
- A converter from analog to digital cannot recover quality the analog signal lost.
- Adding audio to a connector that does not carry it usually needs a separate audio cable.
- Chains of adapters multiply the chances of a handshake failure.
- Copy-protected content may refuse to play through some adapters or older links.
- Direction matters. An adapter that goes from A to B does not necessarily work from B to A.
Resolution and refresh limits
Each connector and version has a maximum amount of data it can carry per second, which sets the highest combination of resolution, refresh rate and color depth. Older connectors usually top out lower. If your screen is stuck at a lower mode than its display specifications suggest, the port or cable is a frequent cause. Also check whether only one port on the display supports its best mode; some displays reserve their top modes for a particular input.
Practical choosing
- Prefer a digital connection whenever both ends offer one.
- Use the port that supports the mode you want, which may not be the first one you notice.
- Buy cables rated for the connector version and the features you intend to use, and skip long adapter chains where possible.
- Keep an analog connection for legacy gear only, since it offers no advantage otherwise.
- When mixing a laptop and a display over USB-C, confirm that video is supported by the specific port and cable.
No connector is best for every case. The right pick is the one that your source and display both support at the mode you need.