There’s no universal label for DP Alt Mode on USB-C ports, and some brands don’t mark them clearly even if supported. The most reliable way is to check your device’s official tech specs.

• Most MacBooks (M1/M2/M3/M4) support video output over USB-C
• Many Windows laptops support it, but not all—especially entry-level models
• On tablets and phones, DP Alt Mode is much less common

You can also test it directly: use a USB-C monitor that supports DP Alt Mode and a full-featured USB-C cable (not a charge-only cable). If nothing shows up, try switching ports or cables.

**Laptops and mobile phones have different combinations of USB-C functions.

Example: MacBook Air + USB-C Monitor

If you're using a MacBook Air (M1, M2, M3, M4), it can be charged via USB-C with as little as 30W to 45W of power. That means: 

• A monitor that supports USB-C PD at 60W or above can easily power your laptop while delivering video over the same cable.

Some BenQ monitors go even further in delivering power and flexibility.

• The BenQ MA Series offers 90W USB-C Power Delivery, plus an additional 15W USB-C port—perfect for charging your iPhone or iPad at the same time.
• For advanced users, the PD2730S and PD3226G feature Thunderbolt 4 with 90W Power Delivery, along with a 15W Thunderbolt 4 port for high-speed peripherals. These models are a great match for most MacBook Pro users, offering stable power and bandwidth for daily creative workflows. For devices that require 96W, the 90W output may charge slightly slower, but is fully compatible.

These models eliminate cable clutter—providing 90W charging for your MacBook, seamless 4K or 5K display output, and additional power for your peripherals, all through a single cable.

Yes—but compatibility depends on what you're trying to do.

USB-C and Thunderbolt ports use the same connector, so they’re physically compatible. You can plug a USB-C device into a Thunderbolt port, and vice versa—but that doesn’t guarantee full functionality.

For example, a USB-C monitor will usually work with a Thunderbolt port for display and charging, as long as it supports DP Alt Mode and Power Delivery. But not all USB-C ports support Thunderbolt-level speed, daisy chaining, or PCIe accessories.

USB 3.1 Gen 2, Thunderbolt 3, and Thunderbolt 4 may look alike, but their performance and feature sets are quite different. The table below compares the key differences at a glance.

No. Charging your MacBook via a USB-C monitor is completely safe, as long asif the monitor supports Power Delivery (PD) and delivers sufficient wattage. macOS manages power input intelligently, so your battery is protected from overcharging or overheating. 

In this case, the monitor’s USB-C functionality has been tested by an Authorized USB-IF Test Lab to verify safe power delivery and MacBook compatibility—ensuring it charges your device reliably without compromising battery health.

This could be due to one of four reasons:

1. The monitor doesn't support USB-C Power Delivery, or the output wattage is lower than what your MacBook requires.

2. The monitor is off or in a power-saving mode.

3. You're using a charge-only or low-wattage USB-C cable

4. Your MacBook is connected to the wrong port. 

Try using a certified USB-C PD cable and double-check the monitor’s specifications for power output

Your monitor might only support charging, not video. To display content, both the MacBook and the monitor must support DP Alt Mode. Also ensure your cable supports both video and power, and the monitor is set to the correct input source.

Yes—if the monitor offers an additional USB-C or USB-A port with Power Delivery. For example, BenQ’s MA Series includes a secondary 15W USB-C port ideal for charging an iPad or iPhone while your MacBook stays connected. 

No. USB-C only refers to the shape of the connector—not what it can do. Some cables only charge. Others support video, data, or high-wattage power. Always check for labels like “4K,” “PD,” or “Thunderbolt Certified.”

Yes. Use a full-featured USB-C cable that supports both video and charging. Avoid USB-C cables designed only for power or data transfer. Look for specs like “4K video,” or “PD” when buying.

Try the following:

1. Use the correct input source on your monitor (USB-C)

2. Restart your Mac with the monitor plugged in

3. Use a different USB-C port or cable

4. Go to System Settings > Displays and click Detect Displays

To confirm if your MacBook supports DisplayPort Alt Mode over USB-C:

1. Check Apple’s official specs: Most MacBook Air and Pro models with M1, M2, M3, or M4 chips support video output via USB-C. Look for “Display Support” or “Thunderbolt / USB 4” in the technical specs.

2. Use a USB-C monitor and a known good cable: If your monitor doesn't display anything, make sure the cable supports both power and video (DP Alt Mode), and that you're using the correct USB-C port on your MacBook (some hubs have data-only ports).

3. Avoid charge-only cables: These won’t transmit video, even if the devices support it.

If your MacBook is from 2020 or later, it's very likely to support DP Alt Mode via USB-C. The most common issue is using a cable that only charges but doesn’t support video transmission. All MacBooks with Thunderbolt 3 / 4 or USB 4 ports support DisplayPort Alt Mode.

Unless you have specific high-performance needs.

Most MacBooks support DisplayPort over USB-C, so a regular USB-C monitor with DP Alt Mode works perfectly for everyday tasks like browsing, streaming, or even photo editing.

Choose a Thunderbolt monitor only if you need daisy-chaining, external SSDs, or rely on a Thunderbolt dock for accessories.