Plugable USB-C Voltage & Amperage Meter for High Power Devices (240W EPR)

Google Pixel phones support USB-C DisplayPort Alternate Mode for wired video output, but due to Android OS limitations, they cannot produce two extended external displays using MST, DisplayLink, or Thunderbolt docking technologies. This is a platform constraint, not a hardware or dock issue.

Understanding the Limitation

Google Pixel phones are limited by the Android operating system’s handling of external displays. While many Pixel models (such as the Pixel 7 and Pixel 8 series) support USB-C DisplayPort Alternate Mode, they can only output to a single external display at a time. Android is designed primarily for screen mirroring, and extended display support is extremely limited across Android phones.

Key Point:

Android OS currently restricts Pixel phones to one external display, regardless of the dock or adapter used.

Dock Behavior with Pixel Phones

MST Docks (e.g., Plugable UD-MSTH2)

MST (Multi-Stream Transport) requires the host device to support splitting one DisplayPort signal into multiple independent video streams. While common on Windows and many Chromebooks, Pixel phones do not support MST for extended displays.

When using an MST dock, a Pixel phone will:

• Output to one external display only, or
• Mirror the same content to two connected monitors
• Dual extended desktops are not supported

DisplayLink Docks

DisplayLink technology works on Android through a companion app (e.g., DisplayLink Presenter). However:

• Android only supports a single external display via DisplayLink
• DisplayLink docks cannot be used to achieve multiple extended monitors from a Pixel device
• DisplayLink is not recommended for dual display use on Android

Thunderbolt Docks

Google Pixel phones are not Thunderbolt-certified hosts. When connected to a Thunderbolt dock:

• They revert to basic USB-C DisplayPort Alternate Mode
• Only a single mirrored display is possible

Visual Summary

Recommended Alternatives

If your goal is to use two independent external displays, consider the following instead:

• Windows laptops with DisplayPort MST support
• Chromebooks that support MST

Frequently Asked Questions

Q: Can I extend my Pixel’s screen to two monitors using any method?
A: No. As of now, Android does not support multiple extended displays. Only mirroring to one display is possible.

Q: Does DisplayLink allow multiple displays on Android?
A: No. Even with DisplayLink’s Android app, you are limited to one external display.

Q: Why do Windows and ChromeOS devices work with MST but not Android?
A: Android lacks support for DisplayPort MST and advanced GPU capabilities required for multiple display outputs. This is a software/platform-level limitation.

Conclusion

While Google Pixel phones are capable of driving a single external display, dual extended monitors are not possible due to Android OS restrictions. This applies across all dock types, including MST, DisplayLink, and Thunderbolt. For users requiring robust multi-display setups, we recommend using a Windows or Chromebook device that supports MST alongside a compatible docking station like the Plugable UD-MSTH2.

If you have any questions or need help selecting a compatible dock, reach out to our support team at support@plugable.com.

The USBC-VAMETER and USBC-VAMETER3 display voltage, amperage, and the calculated wattage directly on the screen. To manually calculate the wattage (how much power a device is using), simply multiply the voltage by the amperage.

How to Calculate Wattage

The power (P) in watts (W) is equal to the voltage (V) in volts times the current (I) in amps (A), using the formula: P = V × I.

Example: If a device is charging at 20V and 5A, the calculation is 20V × 5A = 100W.

Applicable To

• Plugable USBC-VAMETER
• Plugable USBC-VAMETER3

In our testing we’ve found that compared to a professional multimeter, our USBC-VAMETER3 is within +/- 3% of the true value (measured at 20V). 

Please note that this meter is not meant to replace professional USB-C testing equipment, it is designed for quick and easy measurements for users at any skill level.

The USBC-VAMETER3 will display voltage, amperage, and the calculated wattage on screen. If you would like to manually calculate the wattage (how much power a device using) you can follow this simple formula: 

The power (P) in watts (W) is equal to the voltage V in volts (V) times the current (I) in amps (A), P = V × I.

Example: A device is charging at 48V, 5A: 48V × 5A = 240W.

The USBC-VAMETER is designed for USB-C Power Delivery Revision 3.0 (5-20 volts, up to 5 amps, 100 watts maximum). Most devices currently on the market use PD R3.0.

The USBC-VAMETER3 is designed for the latest USB-C Power Delivery Revision 3.1 Extended Power Range (EPR) (5-48 volts, up to 5 amps, 240 watts maximum). As of July 2022 there are not many EPR devices available yet, but a good example is the 16" Apple MacBook Pro with 140W charger.

If unfamiliar with Extended Power Range feel free to take a look at our blog post on this topic here: https://plugable.com/blogs/news/what-is-240w-usb-extended-power-range-epr

The new USB Power Delivery specifications allow for the delivery of up to 240W via a USB Type-C cable (an increase from the previous 100W max). The previous Power Delivery range has been relabeled as Standard Power Range (SPR), and the new specifications (between 100W and 240W), have been labeled as Extended Power Range (EPR).

For a more in-depth look feel free to check out our blog post on this topic here: https://plugable.com/blogs/news/what-is-240w-usb-extended-power-range-epr

No, Plugable products do not support the Apple SuperDrive.

Why do Plugable products not support the Apple SuperDrive?

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

Applicable To

• All Plugable brand products

While USB-C and Thunderbolt share the same physical rounded rectangle connector they operate in fundamentally different ways.

The Main Differences Aren't Physical

USB 3 at 5Gbps and 10Gbps with Type-C - often simplified to USB-C - is both the hardware connector standard, and the included data types: USB 5Gbps or 10Gbps data rates, as well as optionally DisplayPort Alternate Mode video and USB Power Delivery for powering and charging both host computers, and downstream devices.

Thunderbolt, specifically Thunderbolt 3 and newer and USB4 use the same physical USB Type-C port, and support a backwards compatibility with USB-C devices, however the signaling and data structure is completely different. Both Thunderbolt and USB4 operate at between four to sixteen times the speed of USB 3. While USB offers optional display and charging, these are mandatory for Thunderbolt hosts. The way display data is transmitted is also different.

DisplayPort Alternate Mode for USB 3 occupies two or four of the physical data lanes in the USB Type-C connector and cable. Tunneled DisplayPort video in Thunderbolt (and USB4) packetizes the DisplayPort video data and transmits it within Thunderbolt/USB4 data packets. Tunneled DisplayPort allows for more native DisplayPort streams enabling multiple external displays at higher resolutions and refresh rates.

Power Delivery is the USB Type-C (as in the port) charging and power standard - this allows a power source and device to negotiate a voltage and maximum amperage both devices can support. For example a phone might negotiate a 9V 3A charge rate which is close to optimal for a phone size battery, while a notebook computer is more likely to negotiate 20V 5A both for improved battery charging and to power the system under moderate to heavy workloads.

Why USB-C and Thunderbolt Capabilities Differ

USB Type-C is a connector standard where features such as video output (DisplayPort Alt Mode) and USB Power Delivery (PD) are optional and depend on the host device manufacturer. In contrast, Thunderbolt sets mandatory performance and hardware requirements across data, video, and power protocols.

• USB 3.0 / 3.1 Gen 1: Up to 5Gbps data transfer speed.
• USB 3.2 Gen 2: Up to 10Gbps data transfer speed.
• USB 3.2 Gen 2x2: Up to 20Gbps data transfer speed. This is very rarely implemented and most computers do not support it.
• Thunderbolt 3: Up to 40Gbps data transfer speed, supports dual DisplayPort 1.2 enabling two 4K or a single 5K displays, USB, DisplayPort, PCIe over a single cable, and up to 100W Power Delivery.
• USB4: Up to 40Gbps data transfer speed, supports DisplayPort 1.4 either one or two external displays, PCIe, and optional Thunderbolt 3 compatibility, USB 3.2 Gen 2 10Gbps, and Power Delivery.
• Thunderbolt 4: Up to 40Gbps data transfer speed, supports dual 4K or single 8K displays, USB4 compatibility, USB 3.2 Gen 2 10Gbps, and Power Delivery.
• Thunderbolt 5: Up to 80Gbps bi-directional bandwidth (DisplayPort up to 120Gbps using Bandwidth Boost), supports dual 6K or single high-refresh-rate 8K displays, PCIe, and backward compatibility with Thunderbolt 4 and USB4, USB 3.2 Gen 2 10Gbps.

Effectively each tier from this list supports all of the features of the tier above as well as some new features. Thunderbolt 4 is Intel's implementation of USB4 with all optional features enabled.

How to Identify Ports and Ensure Compatibility

• Port Identification: Thunderbolt ports are usually marked with a lightning bolt symbol with a downward pointing triangle at the bottom point, this should be next to the port, while USB-C ports may be unmarked or feature symbols indicating power delivery (a simple lightning bolt is common) or DisplayPort capabilities ("DP" logo is often used). Always refer to device technical specifications for confirmation.
• Connecting Thunderbolt Devices to USB-C Ports: Thunderbolt 3, 4, or 5 devices connected to standard USB-C ports typically operate at reduced capabilities, such as lower speeds or fewer display outputs.
• Connecting USB-C Devices to Thunderbolt Ports: USB-C devices connected to Thunderbolt ports function normally, but cannot take advantage of full Thunderbolt features.

Applicable To

• Plugable docking stations, hubs, and video adapters
• USB-C standards (USB 3.0, 3.1 Gen 1, 3.2 Gen 2, 3.2 Gen 2x2, USB4)
• Thunderbolt standards (Thunderbolt 3, Thunderbolt 4, Thunderbolt 5)

If you have any questions please feel free to contact us at support@plugable.com and we'll be happy to help!

Many users assume that USB-C devices can work with older Thunderbolt 2 Macs if they use a Thunderbolt 3 to Thunderbolt 2 adapter, such as the one made by Apple. However, this is not the case. These adapters are specifically designed to support Thunderbolt devices only - not standard USB-C peripherals.

While Thunderbolt 3 and USB-C share the same connector type, they use different underlying data protocols. Non-Thunderbolt USB-C devices, rely on USB standards for data and power. The Thunderbolt 3 to Thunderbolt 2 adapter does not carry USB signals; it only passes Thunderbolt data. Because of this, plugging a USB-C device into a Thunderbolt 2 Mac using this adapter will not work - the computer will not detect or communicate with the device.

If you need to connect peripherals to a Thunderbolt 2 system, we recommend using a USB-A dock or hub (if available on your system). This ensures compatibility without relying on unsupported adapter chains.

In short, even though the connectors may fit, USB-C devices are not compatible with Thunderbolt 2 Macs via Thunderbolt adapters - only Thunderbolt devices will work in that setup.