Video splitters, extenders and docks are the devices that share, stretch or expand a video signal: splitters send one source to several screens, extenders carry HDMI or DisplayPort over long distances, and docks add video outputs and extra ports to a laptop. They suit home offices, meeting rooms, classrooms and shops that run more than one display.
Splitters, extenders and docks are the three main product types to look for here.
How to choose a video splitter, extender or dock
Splitter, switch or dock. A splitter copies one source to several screens, so every display shows the same picture. A switch does the opposite, sharing one screen between several sources. If you want a different desktop on each monitor, you need a dock or a graphics output for each display, not a splitter.
Resolution and refresh rate. Check that the device supports the resolution and refresh rate of your screen, for example 4K at 60 Hz rather than 4K at 30 Hz. The lowest rated device in the chain sets the limit, so the cables, source and display all need to match. Older HDMI versions may force a lower refresh rate at 4K.
Extender distance and cable type. Ordinary HDMI cables can lose signal over longer runs, especially at 4K. Extenders usually send the signal over network cable or fibre, and each model states its maximum distance for a given resolution. Pick a model rated for more than the run you need, and check whether it uses a single cable or a separate transmitter and receiver pair.
Dock connection and ports. Docks connect through USB-C, Thunderbolt or USB-A, and the video they can carry depends on your laptop. USB-C ports need DisplayPort support to output video, and Thunderbolt ports generally handle several displays. Count the video outputs you need, then add Ethernet, USB and card reader ports as required.
Copy protection and compatibility. Streaming boxes, Blu-ray players and game consoles use HDCP copy protection, and a splitter or extender that does not support it can produce a blank screen. Mac laptops generally do not support MST, so a single-output hub may not extend the desktop across several screens. Check these points against your own equipment before buying.
Brands and product types
- Splitters: these take one HDMI or DisplayPort input and give two, four or more outputs, which suits shop displays, digital signage and presentations.
- Extenders: these use a transmitter at the source and a receiver at the screen, and are the usual answer for projectors, boardrooms and wall-mounted displays far from the source.
- Docks: these connect to a laptop through one cable and add video outputs, USB ports and often Ethernet for a tidy desk setup.
No individual brands are listed in this category at the moment, so check the product listings for the makes available.
Frequently asked questions
What is the difference between a video splitter and a video extender?
A splitter sends one video source to several displays, while an extender lets a signal travel further than a normal cable allows. A splitter changes how many screens you can feed, and an extender changes how far away they can be. Some products combine both, but most do one job.
Can a splitter give me a different image on each monitor?
No, a standard splitter shows the same image on every screen. To extend your desktop across several monitors, you need a dock, a multi-output adapter or a computer with enough video outputs. Check that your laptop supports multiple displays through its USB-C or Thunderbolt port.
How far can an HDMI extender send a signal?
It depends on the model, the cable and the resolution. Many extenders using network cable are rated for several tens of metres at 1080p, and the distance is often shorter at 4K. The product specifications state the maximum distance for each resolution, so match that to your cable run.
Do I need a dock with Thunderbolt or will USB-C do?
USB-C is enough for one or two displays and basic ports if your laptop supports video output over USB-C. Thunderbolt suits higher resolutions, several displays and faster storage. Look at your laptop's port label and specifications before choosing.
