MST is a DisplayPort (DP) 1.2 and newer feature that allows multiple displays to be connected to a single video output. This can be done using a MST hub or by daisy-chaining multiple MST-enabled displays. This technology is driverless, and can be used for seamlessly setting up hotdesking or work from home setups. However, there are some common problems that can occur with these devices.

Display Resolution

While our MST devices can support up to two 4K 60Hz external displays, users of older Intel CPU versions such as the 10th generation Icelake and 11th generation Tigerlake may find that their CPU only supports dual 4K 30Hz, or dual 1080p 60Hz external displays when connected to an MST-based docking station.

Based on internal testing, Plugable expects laptops that support DP 1.4 (Intel 12th gen CPUs or newer) to support up to two 4K 60Hz external displays. Older DP 1.2 hosts typically only support dual 1080p 60Hz external displays.

ARM-based Compatibility

ARM-based systems also do not universally support MST. Whether or not a particular ARM system supports MST depends on the specific SoC (System on a Chip) that is used in the system. Some SoCs such as the Texas Instruments DRA829J do support MST, while others such as the MediaTek MT8127 do not.

If you are unsure whether or not your ARM-based system supports MST, you can check the specifications of your system processor to see if it mentions MST support.

Chart of external display performance for various hosts

Connection issues: (USB-C/Video Cables)

Another potential source of issues are the cables used to connect your dock to your laptop, and your monitors to the dock. 

To connect your dock to your laptop, make sure that you are using a USB-C cable that supports DisplayPort Alt Mode. Plugable recommends using the cable that was provided with your device.

When choosing a video cable for MST, it is important to make sure that the cable supports the desired resolution and refresh rate. To be fully compatible with our MST products, you will want a cable that supports DP 1.4 with a maximum total bandwidth of 32.4Gbps. That gives it enough bandwidth to handle two 4K UHD streams at up to 60Hz. Plugable recommends using the cables that were included with your monitor.

If there are still connection or resolution issues despite using the correct cables, Plugable also recommends swapping out the cables to help determine if the original ones were faulty.

Driver/OS issues: (Staying up to date)

The last major source of compatibility issues with MST-based docks is the operating system your laptop is running. While modern laptops with MST compatible processors that are running operating systems such as Windows 11,10, 8, 7, and ChromeOS do support MST displays and devices, MST is currently not supported by macOS hosts. 

You will also want to make sure that all system and graphics driver updates are applied to avoid any problems with outdated drivers or OS versions.

However, if you have confirmed that all your hardware is compatible and you are still not seeing the expected display results, please feel free to to reach out to our support team as support@plugable.com

For full functionality, the UD-MSTHDC requires at least one of the following ports to be on your laptop:

• Thunderbolt 3 or 4 port
• USB Type-C ports with Alt Mode (DP) and Power Delivery (PD) support

Additionally, the laptop needs to have an Intel 11th gen or newer CPU to support all dock resolutions, as noted below:

• DP 1.4 hosts support up to two 4K 60Hz external displays
• DP 1.2 hosts support up to two 1080p 60Hz external displays

The UD-MSTHDC's power button controls power to the docking station itself, and will not turn on or off the connected host.

The button will be on by default, and can be used to manually turn the dock off, and then back on if needed.

What is MST?

MST stands for Multi-Stream Transport and is based on DisplayPort Technology, allowing multiple uncompressed video streams to be delivered over a single DisplayPort connection (a process known as multiplexing). MST can be used over several different video port mediums, such as DisplayPort, Mini DisplayPort, Thunderbolt 3 or 4, and USB-C ports that support DisplayPort (Alt-Mode).

Two types of connections can be made when using MST. A “daisy-chain” connection where you can link multiple monitors together or an “MST Hub” configuration that can split one DisplayPort cable into multiple video outputs.

For MST to work in a daisy-chain or MST Hub configuration, monitors must support either DisplayPort 1.2 connection (or higher) or Thunderbolt, provide a video “out” port on the monitor, and have MST mode enabled in order for the monitors to work together. Note that HDMI is not supported. 

Daisy-chain example

In many cases, a monitor will not have a video “out” option; this is where an MST Hub will become necessary to break out the video signal to each monitor individually. 

Plugable's USBC-11IN1E shown in this MST Hub example

Will I need additional software to use MST?

MST does not require any additional software and will connect directly to the host GPU in order to bring high-resolution, uncompressed video that is beneficial in a variety of applications such as graphics design and video editing. Resolutions will vary depending on the specifications of the GPU. DisplayPort 1.4 GPUs will support higher resolutions and refresh rates than DisplayPort 1.2, for example. 

It is recommended to use the most up-to-date GPU drivers from your laptop or GPU manufacturer.

Which operating systems support MST?

MST is supported by Windows 11, 10, Windows 8/8.1, Windows 7, and Chrome OS.    
MST is currently not supported by macOS or Mac OS X.

Compatible Plugable MST devices

Now that we have a better idea of MST, Plugable is excited to introduce several MST compatible hubs and docking stations that can help boost productivity and provide external monitor support, including the ability to provide other capabilities such as USB, Ethernet, and even Audio. Some supported products are,  

• USBC-11IN1E
• UD-3900C4
• UD-MSTHDC
• UD-MSTH2

Some of our Thunderbolt supported products include,

• TBT3-UDC3
• TBT3-UDC1
• TBT3-UDZ
• TBT4-UDZ 

Most Windows notebook computers power management settings will default to putting the computer to sleep with the lid closed, regardless of any external displays, keyboard, or mouse connected to the computer. If this is happening but you would prefer the system to remain active with the lid closed utilizing the external display or displays, these settings can be changed by performing the following:

For Windows 10:

1. Start by right-clicking on the Start button and select Power Options from the menu.
2. From the right side of the Power Options settings page, select the blue link for Additional power settings

   

3. From the choices present on the left-hand side of the Power Options window, please click on Choose what closing the lid does
4. Make sure the setting for When I close the lid under the Plugged In column is set to Do Nothing

   

5. Click the Save Changes button and restart the system (making sure that the laptop’s power adapter is also connected) and test the behavior again.

For Windows 11:

1. Start by right-clicking on the Start button and select Power Options from the menu.

   

2. In the upper left corner of the settings window, in the search box, type "lid" then select Change what closing the lid does from the search results

   

3. Make sure the setting for When I close the lid under the Plugged In column is set to Do Nothing

   

4. Click the Save Changes button to apply the new settings.

Closing the lid should no longer put the computer into sleep mode when an external display and power source is connected, instead one of the external displays should now become the Primary display with the desktop icons instead of the laptop's built-in display.

The lid may still need to be opened to perform the following tasks:

• To power on the computer from a fully powered off state
• To log into the computer if logged out or if the computer is restarted with the lid closed
• To wake the computer from a deep sleep state ( hibernation, or Windows hybrid sleep states )

If your Windows laptop will not boot properly when a docking station is connected to the laptop, most often the cause is an external device connected to the docking station (for example an external USB storage drive) as opposed to the dock itself. 

If you are affected by this condition, please follow these steps in order to isolate the behavior further:

1. Disconnect all USB devices from the docking station and put them aside for the moment.
2. Disconnect any displays connected to the dock's video outputs.
3. Disconnect any audio devices connected to the dock's audio ports (if present).
4. Disconnect the Ethernet network cable from the dock's Ethernet port (if present).
5. The only remaining connections should be the dock's power adapter cable and the USB cable used to connect it to the laptop. No other external devices should be connected to the dock.
6. While in this state, reboot the laptop to test the behavior.
7. Assuming the laptop boots as expected, please reconnect each device back to the dock one at a time and reboot after each one to test the behavior again. Please reconnect the displays first, then the audio devices, then the Ethernet cable. Please reconnect any USB devices to the dock last, again rebooting after each one is added to test the behavior.

In our experience helping others, the most common cause of this behavior is an external USB storage drive connected to one of the dock's USB ports.  In some cases, a laptop may try to boot from an external storage drive by mistake as opposed to the laptop's built-in storage drive.  Since most external USB storage drives are not 'bootable', this can interrupt the boot process. 

If this behavior occurs, the most common way to mitigate the behavior is to access the laptop's System BIOS (also known as UEFI firmware) to change the 'boot order' settings to ensure that the laptop's internal storage drive is the first boot option.  Doing so helps ensure that the laptop will not try to boot from an external USB storage device. 

Every laptop system is different, so the best resource for accessing the System BIOS and changing the settings is the manual for the laptop provided by the laptop manufacturer.   

Below is a list of power adapter models used by Plugable docking stations. We offer refurbished replacement power adapters on eBay as they are available for purchase, however, we may not have replacement power adapters available for all of our docking stations.

If the power adapter for your docking station or region is not listed, out of stock on eBay or if you have any other questions regarding replacement power adapters for our docks please contact us at support@plugable.com and we will be happy to assist further.

We offer a 30-day return period for our replacement power adapters listed on eBay.

If your package is missing one or more of the items that should be included with your Plugable dock (included items are listed on a chart on the side of the box), start by double checking if the part is still in the packaging. Pieces can occasionally get stuck in the corners under the main insert in the box.

If you are still unable to locate the piece, please contact support@plugable.com with the following information:

1.  Amazon Order ID (or other proof of purchase) associated with your Plugable device.

2. A description of the parts that are missing from your order.

3. Your preferred shipping address (and a phone number associated with that address).

4. The serial number of your Plugable Dock.

Most Plugable docks do not officially support monitors over 60Hz including 120Hz or 144Hz refresh rate unless otherwise specified on the Plugable product page or listing. 

DisplayLink USB Graphics technology and Silicon Motion based docking stations and graphics adapters, like our USB 3.0 dual display and USB Type-C triple display docking stations, are limited to 60Hz fresh rate by the USB graphics controller hardware.

USB Type-C DisplayPort Alternate Mode docking station and ports on our USB Type-C Triple Display Docking Stations can support higher refresh rates, but may be limited by the computer's capability and available bandwidth to the docking station.  Additionally, when paired with DisplayLink or Silicon Motion USB graphics, having displays at different refresh rates may reduce overall system performance.  Due to this we normally recommend limiting all connected displays to 60Hz refresh rate when using DisplayLink and Silicon Motion graphics technology with directly connected, or USB Type-C DisplayPort Alternate Mode controlled displays.

Monitors with refresh rates higher then 60Hz may be connected to a docking station operating at up to 60Hz, or connected directly on the computer's HDMI or DisplayPort to ensure the display is powered by the system's native GPU.

Unfortunately Plugable products do not support the Apple SuperDrive.

The Apple SuperDrive has stringent power requirements that can only be met by directly connecting the SuperDrive to your host laptop. As a result at this time Apple recommends only using their USB-C adapter cables. You can find more information on that here → How to connect the Apple USB SuperDrive

If you have purchased a Plugable product to use with your Apple SuperDrive, and would like some additional assistance please do not hesitate to reach out. You can do so by emailing support@plugable.com, or going to Plugable.com/Support.

Please Note

The below guide is an advanced troubleshooting step, and we do not recommend doing so unless you are comfortable manually altering files on your Apple product running macOS. You may not be able to perform the below troubleshooting step if you are unable to execute administrative credentials on your laptop. Please reach out to our support first if you do not wish to attempt the below instructions. You can do so at Plugable.com/Support

How to delete a specific Ethernet adapter from your Network devices on macOS

1. Click on the Apple logo in the top left corner of your primary monitor, and select ‘System Preferences’
2. Next select ‘Network’ in the ‘System Preferences' window.
3. In the now visible list, please select the Plugable Ethernet, or Thunderbolt Ethernet device that may not be working as expected.
4. Once selected click on the minus button in the bottom left of the network window.
5. Click on Apply in the bottom right.
6. Next click on the plus button in the bottom left of the network window, and add the previously removed device.
7. Click on Apply in the bottom right.
8. Test to see if this has resolved the unexpected behavior, and assure that your Ethernet is now working.
9. If this does not resolve the problem, please proceed to the next section (As noted previously the next section is for advanced users only!)

I am still unable to get my Ethernet connection working on my Mac

If this is the case please reach out to our support team. When you do please include a diagnostic log gathered using our PlugDebug tool (instructions are provided on the PlugDebug page). If you are not able to gather the PlugDebug diagnostics do not worry we are still here to help! Please reach out to our support team at support@plugable.com or Plugable.com/Support with a detailed description of your problem, and the model of Plugable product you are using.

We are often asked if it is okay to leave a notebook computer connected to one of our USB-C docking stations with Power Delivery for extended periods of time.  The short answer is yes, it is no different from leaving the laptop connected to the manufacturer's original USB-C power supply for the same time.  The long answer is yes for modern laptops, and maybe for older (1990s-early 2000s laptops) and involves going into the different battery technologies used in consumer electronics devices.

Another common question is if it is possible to use the docking station but to disable powering and charging the computer.  When a modern notebook computer runs on battery power it will often set the system to a reduced power state which may impact performance, or connected devices and we recommend always powering the computer when using a desktop docking station.  For all of our docking stations that provide power to the host computer this will not affect the lifespan of the computer's battery.

Modern Laptop Batteries: Lithium-Ion

Lithium-ion (li-ion) batteries are found in a wide range of consumer electronics from notebook computers and cell phones, to electric cars, power tools, and wearable electronics like wireless earbuds.  Li-ion offers fast charging, high-current discharging, fairly long service live compared to other rechargeable battery technologies and are relatively inexpensive.

The life-span of a rechargeable battery depends on many factors including age, temperature history, charging patterns, the chemical composition of the specific battery, and usage.  For example batteries stored at 100% charge will degrade faster than batteries stored at 50% charge, this is why most consumer electronics devices arrive from the manufacturer with between 25% to 75% charge.

Lithium-ion batteries are consumable components, however in most modern computers, cell phones, and tablets these are not user serviceable components.  To help maintain the battery all modern computers and most consumer electronics will include battery charge and protection circuits.  These can be fairly simple, charging up the battery at preset rates depending on the charge level to help maintain the battery life, or complex software controlled charging that monitors battery temperature, voltage and current draw to maintain the fastest charging while maintaining the battery longevity.

Modern notebook computers can be left connected to the original power cable or a docking station with charging capability for extended periods, and do not benefit from regular discharge/recharge cycles.  Our docking stations with charging capability rely on USB Type-C Power Delivery to power and charge compatible computers.  USB Type-C Power Delivery is a negotiated charging protocol between the host computer and the docking station or USB Type-C power supply, this allows the computer to draw only the power it requires, and even select the best voltage level for powering the computer.  In combination with a computer's built-in battery charging controller the computer is capable of maintaining the battery's optimal state even when left connected to a power source for an extended period of time.

Legacy Laptop Batteries: NiCad and NiMH

Older laptops, from the 1990s and some early 2000s, as well as some consumer electronics, and most rechargeable AA or AAA battery replacements use Nickel-Cadmium (NiCad) or Nickel-Metal Hydride (NiMH) batteries.  These batteries are slower to charge and discharge than li-ion batteries, and require very simple charge controllers, and in some cases can even be trickle-charged ( very low-current continuous charging ) if desired.

These batteries generally don't have smart charging controllers and to prolong the life of the battery required "training" or fully discharging and recharging the battery every so often.  Many laptop manufacturers recommended fully charging and discharging a new laptop 2-3 times to train the battery, this is not necessary with modern laptops.

Conclusion

Modern notebook batteries are managed by the computer's built-in battery charging circuit, and require little to no user intervention to maintain optimal battery health.  It does not harm the battery to leave the computer connected to an external power supply, so long as the computer is being used regularly.  If the computer is to be stored for a prolonged period then discharging the battery to between 50-75% can help to maintain the battery life.

Batteries are consumable components and degrade over time, however modern notebook computers can extend the battery life generally to meet or exceed the life of the computer's other electronic components.

It's not uncommon for users to notice a certain level of heat generation from electronics and by extension, Plugable products during operation. In this knowledge base article, we'll explore the reasons behind this heat generation and why it is considered a normal experience within reasonable limits.

Electronics, by their nature, generate heat during operation. This is primarily a result of the electrical current flowing through various components, such as integrated circuits, transistors, and other electronic elements. As Plugable products are designed to efficiently process and transfer data (among other functionality), some level of heat generation is inherent.

Factors Influencing Heat Generation:

1. Power Consumption: The power consumption of a device directly influences the amount of heat it generates. Higher power usage, especially during data transfer or charging processes, can lead to increased heat.
2. Enclosure Design: The design of the product's enclosure and its ability to dissipate heat play a crucial role. Adequate ventilation and heat sinks are often incorporated to manage and disperse generated heat effectively. This is evident in our TBT3-UDZ and TBT4-UDZ designs. The metal case in these docks are designed to function as a heatsink with thermal pads placed throughout the enclosure. This allows heat dissipation from inside to the outside, but will also make it feel as if the device is “too hot”. 
3. Ambient Temperature: The external environment may also play a role. Higher ambient temperatures can contribute to increased perceived heat from the product. This means that summer temperatures may increase the heat generation of not just Plugable products, but many other electronic devices.

Normal Heat Levels: While it is normal for electronic devices to generate heat, Plugable products are engineered to operate within safe temperature ranges. We conduct rigorous testing to ensure that the heat generated during normal operation falls within industry-standard safety parameters. While not all products are or need to be UL certified, we try to go by UL guidelines for thermal readings. The UL threshold is 77C/170.6F, and we aim for around 71C/160F.

Tips for Users:

1. Ventilation: Ensure that Plugable products have sufficient ventilation around them. Avoid placing them in enclosed spaces where heat dissipation may be impeded.
2. Usage Patterns: Intensive tasks such as high-speed data transfer or charging multiple devices simultaneously may result in increased heat generation. This is generally normal but may be more noticeable in such scenarios.
3. Accessories: A number of our devices will allow for the connection of USB accessories and as such, these will require power. If too many “power-hungry” devices are connected, this will cause the device to run much hotter than expected. Be sure to keep in mind the power limits of your dock/device.

In conclusion, experiencing heat from Plugable products is a normal aspect of their operation. Users can rest assured that we prioritize the safety and efficiency of our devices. By understanding the factors influencing heat generation and following simple usage guidelines, users can make the most of their Plugable products while ensuring a reliable and efficient user experience.

If you have installed your DisplayLink-enabled docking station or graphics adapter and downloaded the DisplayLink software, but see that no displays are working properly, you may need to enable “Screen Recording”. In this guide, we will go over a short list of steps to enable this permission, and get your DisplayLink device up and running!

As of macOS Catalina (version 10.15), DisplayLink drivers that are installed require that the “Screen Recording” permission be granted by the user. While this permission, when used in conjunction with DisplayLink is not recording in a traditional sense, it does allow DisplayLink to access the pixels it needs to render images (mirrored or extended). It then sends these pixels over USB from the computer to the display connected to your DisplayLink connected device.

Note: It does not capture or send any data.

During the installation process for the DisplayLink drivers, you will be requested to allow “Screen Recording” for DisplayLink. Additionally, you may see a notification within the DisplayLink application and when a new device is connected. However, we understand sometimes these may get lost in a sea of information and other notifications.

How do I know if the Screen Recording permission hasn’t been set? Reference the image below to check in your “Privacy & Security” settings

If you have not enabled “Screen Recording”, please follow these few instructions to enable it.

1. Click on the Apple icon (defaults to the top left corner of your screen) and select “System Preferences
2. Navigate to and click “Security & Privacy”
3. In this window, select “Privacy”
4. A list will be presented, scroll until you find “Screen Recording” and click on it
5. Displayed on the bottom left, there is a lock icon, click on this to make changes
6. If prompted, login using your computer credentials to make changes
7. Check the box next to DisplayLink Manager
8. You will be promoted to “Quit & Reopen”, click this button
9. Click on the lock icon once more to save your changes

Note: Some of these steps may vary slightly based on your macOS version

You should now be able to see your displays on your docking station or adapter. If you have completed the above steps successfully and still do not see your displays, please be sure to reach out to our support team at support@plugable.com.

The Windows Firewall may block some networking features when the local network is not set to Private.  This article will describe the process for setting the local network, either wired Ethernet or Wi-Fi to be a Private network.

Windows 11

1 - Connect the computer to the network, either wired or wireless

2 - Open the Windows Settings - right-click on the Start Menu and select “Settings” from the pop-up menu

3 - On the left column select “Network & internet”

For Wired Networks

4 - Select the “Ethernet” option

5 - The connected network should be expanded, if not click on “Network Connected" to expand the section

6 - Select the “Network profile type” either “Public network” or “Private network” to suite your needs

For Wi-Fi Networks

4 - Select the “Wi-Fi” option

5 - Select your Wi-Fi network name “properties”

6 - Select the “Network profile type” either “Public network” or “Private network” to suite your needs

Windows 10

1 - Connect the computer to the network, either wired or wireless

2 - Open the Windows Settings - right-click on the Start Menu and select “Settings” from the pop-up menu

3 - Select “Network & Internet” fro the bottom section

4 - Select the “Ethernet” option from the left pane

5 - Select the “Connected” network from the right pane

6 - Select the “Network profile type” either “Public network” or “Private network” to suite your needs

Windows PowerShell

If the option does not show up in the Windows Settings GUI, or if you prefer to use the terminal.

1 - Open a new terminal: Right-click on the Start Menu and select “Terminal” 

2 - Run the following command to list the available networks

Get-NetConnectionProfile

PS C:\Users\plugable> Get-NetConnectionProfile
Name                     : Network
InterfaceAlias           : Ethernet Instance 0
InterfaceIndex           : 7
NetworkCategory          : Private
DomainAuthenticationKind : None
IPv4Connectivity         : Internet
IPv6Connectivity         : NoTraffic

3 - Run the following command to set the network to Private

Set-NetConnectionProfile -Name Network -NetworkCategory Private

Where “Network” is the network name from step #2 and “Private” can be either “Public" or “Private”

 A common question we receive is whether it is okay to use a dock or hub that provides different wattage compared to the power adapter included with the laptop, especially if the dock or hub provides less power than the OEM charger. Short answer: for most use cases, it’s fine! And when using standards-compliant docks, hubs, and chargers like those from Plugable, it’s always safe.

When considering whether a dock or hub has enough power to charge a host, it is helpful to understand how little power is consumed most of the time you’re using your system.

Some details why 60W charging is more than sufficient for typical workloads:

All laptops will come with a power supply directly from the manufacturer. This power supply usually supports the maximum charging rate that the host can support (45W, 60W, 100W, 140W, etc.). However, modern systems are designed to be power efficient while managing their power consumption dynamically, typically using just a fraction of their maximum power draw under typical workloads. Additionally, to preserve battery longevity, most devices will reduce charging rate even when a higher wattage charger is connected. Note that Gaming or Workstation laptops, typically including 180W+ power adapters, may have special power requirements.

Even during high-power tasks such as video editing, hosts may only pull greater than 60W for brief periods of time. In these instances, you may notice the battery charges slower, or in some cases even slowly discharges. This is not indicative of a faulty power supply or a problem, just a difference in power consumption vs power delivery.

In some cases, for laptops that can charge at higher than 60W over USB-C, it can take longer for the 60W charger to fully charge a host from 0-100% than a 100W charger for example. However, this is usually only relevant for the first 50 or so percent, as the host limits the charging rate exponentially as the battery gets closer to being fully charged. In the 80-100% range, laptops are typically charging at less than 15W. This means that in a configuration where you are connected to the power adapter for long periods of time, like an entire work day, the 60W charger will be functionally identical to a higher wattage power adapter.

Windows laptops – particularly those from Dell, HP, or Lenovo –  may send pop-ups in the OS or messages on boot warning you about a lower charging rate. The messages could be similar to the following:

• “You have plugged in a lower wattage power adapter, USB-C charging device, or power pass-through device. Your system will continue to work, but may not perform at its peak.”
• “Weak charging state, please check power charger.”
• “The AC power adapter wattage and type cannot be determined. The battery may not charge. The system will adjust the performance to match the power available.”
• “The connected AC adapter has a lower wattage than the recommended model – Please connect the AC adapter which was shipped with the system for best system performance”
• “For full performance, connect a higher power adapter”

Despite these warnings, most business and consumer laptops will indeed continue to charge with a lower wattage charger connected, and the messages can often be disabled in your laptop’s BIOS settings.

All this to say that in most use cases, the differences between 60W and higher wattage chargers are minimal, and 60W charging is likely enough to charge most laptops!
 

Plugable SKUs that feature 60W charging: TBT4-HUB3C, USB4-HUB3A, TBT3-UDC1, UD-3900PDZ, UD-6950PDZ, UD-MSTH2, UD-MSTHDC, USBC-PS-60W

What is Alt Mode, and how does it work?

USB-C is a truly versatile connection that supports a range of functions, including power delivery, data transfer, and video. Alt Mode leverages this versatility by repurposing high-speed data pins to enable alternative video data protocols. Many of our docking stations support this protocol, but there is a catch! To take advantage of this feature, your host system must support Alt Mode via the host USB-C port and controller. If the host system and device support Alt Mode, the USB-C ports automatically switch from its default data protocol to the required Alt Mode protocol for video. 

How do I determine if my system supports Alt Mode?

Reviewing your manufacturer's system specifications or user manual is the easiest way to determine if your system supports Alt Mode via the USB-C port, but unfortunately, it’s not always consistent or straightforward. Below, we have included examples of how some system manufacturers mention the capabilities of the USB-C ports on their laptops. This information will usually be included in the user manuals or system specification sheets.

Please note that mention of DisplayPort or DP 1.2, 1,4, and 2.1 indicates Alt Mode support.

Lenovo

HP

Dell

Additionally, some manufacturers, but not all, will also include a DP symbol next to the port to illustrate its ability to support video. If your USB-C port is unmarked, check your user manual or consult the system specifications. 

What about Thunderbolt 4 and USB4?

Unlike earlier iterations of USB-C, which use Alt Mode for video support, USB4 and Thunderbolt 4 primarily use video tunnelling to transmit video over the USB-C connection. Video tunnelling dynamically allocates bandwidth for video and data to ensure optimized performance. If a device does not fully support video tunnelling, your Thunderbolt 4 or USB4-capable system can fall back to Alt Mode, ensuring compatibility with devices that support Alt Mode for video. So you don’t have to worry about a Thunderbolt or USB4 connection supporting USB-C Alt Mode!

Troubleshooting For Alt Mode 

When using a USB-C video cable, adapter, docking station, or hub, it's important to ensure that your laptop supports Alt Mode. If you encounter any issues, the following steps can help you troubleshoot and determine why video may not be working through your USB-C Alt Mode cable or device.

1. First and foremost, check to ensure that your system supports Alt Mode. This is vital as Alt Mode is an optional feature that not all manufacturers include on their systems.
   1. If your system does not support Alt Mode, unfortunately, this is a hardware limitation, and there is no workaround for achieving Alt Mode compatibility. However, it’s possible to still drive external monitors through DisplayLink.
2. Reboot your system and perform a power reset on your docking station or hub (if applicable)
3. If you are using a docking station, ensure that you are using a USB-C cable that supports Alt Mode. 
   1. Not all cables are created equal—USB-C cables that support USB 2.0 only or “charging only” cables are not built to support video. To ensure compatibility, all of our Alt Mode-capable products will come with a USB-C cable that supports this feature.
   2. Do not use USB-C to USB-A adapters, as they are not designed to support video transmission.
4. Be sure to check your operating system's display settings. The connected display can sometimes be disabled within the display settings, or the resolution and refresh may need to be adjusted to match what your device or display can support.
5. Check if your Alt Mode-capable device has any firmware updates listed specifically for Alt Mode.
6. Ensure that your system is up to date with all its latest drivers, firmware, and BIOS, especially your USB and internal graphics controller. Outdated drivers can often lead to connectivity issues, and at times, a BIOS update is needed, which the system manufacturer will generally mention on their official support page.
7. Check BIOS and UEFI settings; some manufacturers add settings that control USB-C functionality. Ensure that your settings are enabled and correctly configured for Alt Mode.
8. Test out another USB-C port on your system if you have more than one. This is beneficial in determining if the issues are related to the specific port.

Benefits of USB-C Alt Mode

Alt Mode over USB-C provides a direct connection to the GPU, allowing you to take advantage of the capabilities of your built-in GPU. This ensures native-level performance without the need for extra software or drivers. As a result, your USB-C Alt Mode-connected display will have reduced latency compared to other methods of adding additional displays, making it perfect for users who require sharp and detailed visuals at optimal refresh rates. Unlike traditional video connectors like HDMI or DisplayPort, which only support video, a USB-C connection with Alt Mode is more flexible and multifunctional, allowing a single connection to carry video, data, and power delivery.

Alt Mode supported devices from Plugable

If your system supports Alt Mode or if you are looking to get more out of your laptop, especially Apple M1, M2, or M3 base chipsets (which are limited to one external display), we have compiled some options below that utilize Alt Mode or a combination of Alt Mode and DisplayLink for even more monitor expandability.

Plugable USB-C Docking Station with HDMI, 60W Laptop Charging
SKU: UD-CA1A

The UD-CA1A is a versatile docking station that enables you to connect a 4K HDMI display via Alt Mode. In addition, it comes equipped with high-speed Gigabit Ethernet, USB 3.0 ports, 3.5mm jacks for headphones and microphone, and will provide 60W of power delivery to your host device—all via a single USB-C port. It is compatible with macOS, Windows, ChromeOS, Linux, iOS, and iPadOS, making it the ideal solution for any setup. You can enjoy seamless plug-and-play functionality and save space with its sleek vertical design or lay it flat for a more subtle look.  

Plugable USB-C 7-in-1 Hub with Ethernet
SKU: USBC-7IN1E  

The USBC-7IN1E instantly transforms a single USB-C with Alt Mode or Thunderbolt port into a versatile hub featuring 2x USB 3.0 ports, a 4K HDMI output, Gigabit Ethernet, and SD and microSD card readers. For hosts that support Power Delivery over USB-C, this hub also supports 100W PD passthrough, allowing you to plug in your included USB-C power adapter to further simplify your setup for greater portable productivity.

The products mentioned above demonstrate the versatility of a single USB-C connection. Plugable offers a wide range of solutions to meet your needs. Whether you are looking for a full-featured docking station that utilizes DisplayLink and USB-C Alt mode, such as our UD-ULTC4K, or a USB-C cable that supports video, data, and charging, like our USBC-240W-1M, you can rest assured that we have you covered. If you have any questions or need help building a solution that takes full advantage of your laptop's USB-C connection, please reach out to us at support@plugable.com.

WWCB stands for Works With Chromebook. It's a certification program where Google collaborates with leading accessory and peripheral partners to ensure certified products, like docking stations, mice, cables, power adapters and more work seamlessly to help you get the most from your Chromebook.

In order for products to be WWCB certified, they must go through rigorous interoperability testing by Google. This helps to ensure external devices operate smoothly with Chromebooks, and helps to add confidence in purchasing products knowing the devices have been verified to meet Google’s standards.

Another benefit of this program is that participating products can utilize Google’s Secure Firmware update mechanism, offering ease and peace of mind for IT departments and users alike. This allows device firmware updates containing security and bug fixes to automatically be pushed by Google via native OS update mechanisms to securely update your WWCB devices via your Chromebook.

WWCB products can be identified with the following Works With Chromebook badge or logo:
 

More information about the WWCB program can be found on Google’s WWCB page:

Plugable offers many products that are compatible with Chromebooks, and our Plugable UD-MSTHDC USB-C Dual Display Docking Station is a device that has received Google’s WWCB certification. The dock has the following supported features for a Chromebook:
 

• 1 x USB-C Port (10Gbps)
• 2 x USB-A Ports (10Gbps)
• 4 x USB-A Ports (5Gbps)
• 1 x Gigabit Ethernet Port 
• 1 x 3.5mm Audio Port
• 2x DisplayPort 1.4 or 2 x HDMI 2.0 Video Ports supporting up to 4K @ 60Hz
• Up to 60W Host Power Delivery via USB-C
• Secure firmware update via ChromeOS

Overview

With the release of Apple’s M3 CPU chips and the Sonoma 14.6 update your base MacBook Air and MacBook Pro systems with M3 chips can now host two external displays natively in clamshell mode. This guide will walk you through the process of setting up and using two external displays with the lid closed on your MacBook Air or MacBook Pro equipped with an Apple M3 chip.

Requirements

Before getting started, ensure you have the following:

• MacBook Air or MacBook Pro with an Apple M3 chip.
• macOS Sonoma 14.3 or later for an M3 MacBook Air or macOS Sonoma 14.6 or later for an M3 MacBook Pro.
• Two external displays with compatible video inputs (e.g., HDMI, DisplayPort, USB-C).
  • A dock or graphics adapter can be used as well.
• External keyboard and mouse (wired or wireless).
• Power adapter or power source for your MacBook
  • A docking station that provides adequate charge can be used in place of the native power adapter, be sure to check the wattage your dock provides.

Steps to Set Up Dual External Displays with the Lid Closed

1. Set Up Your External Keyboard and Mouse

• If you’re using a wired keyboard and mouse, connect them directly to your MacBook or Plugable dock.
• For wireless peripherals, ensure they are paired with your MacBook and functioning properly.
• An AC adapter/power cable of some kind will also need to be connected for clamshell mode to function properly. This adapter can be one from a docking station or the included Apple adapter.

2. Connect Your Displays

• Connect the first external display to your MacBook using the appropriate cable (e.g., HDMI, DisplayPort, USB-C)
• Close your laptop’s lid.
• Connect the second external display using a similar method.
• Ensure both displays are powered on and set to the correct input source.

3. Configure Display Settings

• Open System Settings on your MacBook.
• Go to Displays.
• You should see both external displays listed. Arrange them according to your preference by dragging the display icons.
• Adjust the resolution, refresh rate, and other settings as needed.

4. Enable "Clamshell Mode" (Lid Closed Mode)

• With your external displays connected and set up, close the lid of your MacBook.
• Your MacBook will automatically switch to "Clamshell Mode," where the internal display turns off, and the external displays become your primary screens.
• Ensure your MacBook is connected to a power source to prevent it from entering sleep mode.

5. Check the Display Arrangement

• With the lid closed, check that the external displays are functioning as expected.
• If necessary, re-open the Displays settings to adjust the arrangement, resolution, or other preferences.

Troubleshooting Tips

• No Display on External Monitors: If the external displays are not showing anything, open the lid of your MacBook and check the connections.
• MacBook Sleeps When Lid Is Closed: Make sure your MacBook is connected to a power adapter. Clamshell Mode requires the MacBook to be plugged into an external power source.
• Performance Issues: If you experience lag or performance drops, try lowering the resolution or refresh rate of the external displays.

Thunderbolt Dock Users

With these steps, one can use Plugable Thunderbolt docks to enjoy a dual-display setup without the need for additional software installation. The dock leverages the native capabilities of the MacBook Air M3 and MacBook Pro M3, providing a straightforward and efficient solution for expanding your workspace with additional USB ports, audio, and ethernet (as well as the dual displays).

Additional Resources

If you should need any assistance with your setup, please feel free to reach out to our support team at support@plugable.com.