Name: Plugable UD-3900
Brand: Plugable
SKU: B00ECDM78E

Plugable UD-3900

The UD-3900 makes most sense when replacing the laptop is unnecessary but its connections are inconvenient. It can attach through USB-A or USB-C, so an older machine can keep its keyboard, network cable, and two office monitors together.

By John Morris · Research checked September 11, 2026 · Our methodology

Check on Amazon

Add to comparison

As an Amazon Associate I earn from qualifying purchases. How our links work.

Consider it for

Reusing two HD HDMI office monitors
Computers with USB-A and a separate power connection

Check before buying

No host charging or 4K display support
Not a gaming or HDCP streaming solution

A useful dock for existing HD monitors

Current manufacturer documentation describes two HDMI outputs, with dual screens up to 1920 × 1200 at 60Hz. Older discussions of the UD-3900 may show a different port arrangement. Match the current listing and the actual unit instead of using a photograph from an old review to order cables.

Check the exact configuration and included power supply.

Check on Amazon

The charger remains a separate connection

This dock does not charge the host. That can be acceptable for a desktop computer, or a laptop whose original barrel-plug charger already stays under the desk. If your purpose is specifically to arrive with one USB-C cable and receive power, choose a charging dock instead.

Reserve faster USB sockets for devices that need them

There are two USB 3.0 sockets and four USB 2.0 sockets. Put low-bandwidth input devices on the latter and keep the faster connections free for a drive or another demanding peripheral. DisplayLink installation is part of the display arrangement; a USB-C connector does not turn this into a native-video Thunderbolt dock.

Connections & compatibility

Connection to laptop: USB-A 3.0 or USB-C
Display technology: USB graphics / DisplayLink
Maximum displays (conditions apply): 2 displays maximum
Power to laptop (W): No laptop charging
HDMI sockets: 2
DisplayPort sockets: None
Wired network: Gigabit Ethernet
USB peripherals: 2 USB-A 5Gbps; 4 USB-A USB 2.0
Display requirements: Dual 1920 × 1200 at 60Hz; no 4K
Mac notes: Manual DisplayLink installation required
Windows notes: Windows with DisplayLink software

These are published specifications, not results from hands-on testing. Maximum screen counts depend on the laptop, operating system, connection and chosen resolution.

Check your setup requirements

Sources & specifications

Plugable UD-3900 specifications and compatibility

Research checked September 11, 2026. Product revisions, firmware and operating systems can change compatibility.

Review the current listing

Confirm model, condition, seller, included cables and power supply before ordering.

Check on Amazon

As an Amazon Associate I earn from qualifying purchases. How our links work.

Other Plugable options

Plugable

Plugable TBT4-UDZ

The TBT4-UDZ needs a more careful compatibility check than its four video sockets suggest. Windows and Mac computers use its display arrangement differently, and a USB-C-shaped connection alone does not establish the result.

Up to 4 displays*100W host power*

*Host, software and display conditions apply.

Check on Amazon

Compatibility & details Compare

Plugable

Plugable UD-3900PDZ

A desk with one main screen and two smaller reference monitors is the useful starting point for the UD-3900PDZ. Its three HDMI sockets are not equivalent: one carries native USB-C video, while the other two rely on DisplayLink software.

Up to 3 displays*100W host power*

*Host, software and display conditions apply.

Check on Amazon

Compatibility & details Compare

Plugable

Plugable UD-3900Z

The UD-3900Z is a vertical dock for a desk that already has two HD screens and a separate laptop charger. Its appeal is keeping those existing parts useful rather than paying for display capabilities the monitors cannot use.

Up to 2 displays*No laptop charging

*Host, software and display conditions apply.

Check on Amazon

Compatibility & details Compare

Understand the setup

Compatibility

DisplayLink vs Thunderbolt or Native USB-C Docks

DisplayLink and Thunderbolt docks can put similar sockets on a desk while taking different routes to the screen. Thunderbolt and native USB-C video use display streams supplied by the computer. DisplayLink creates USB-driven virtual displays with compatible hardware and software. Choose the route from the exact host, monitor plan and application constraints—not from the HDMI count.

Read the guide

Compatibility

Dual Monitors on Mac: Chip Limits, MST & DisplayLink

To use two monitors with a Mac, first identify the exact Mac and chip, then decide whether the two screens will use native display streams, an MST path that may mirror, or DisplayLink virtual displays. Two sockets on a dock answer none of those questions by themselves. The steps below separate Apple’s display ceiling from the dock’s connection method.

Read the guide