Applies to: Plugable TBT4-UDZ only, reviewed 12 September 2026. Host graphics, OS, cable, monitor mode and charging qualifications still apply.
Decide from the host, not the socket count
| Computer path | Documented dock ceiling | Decision-changing condition |
|---|---|---|
| Base M1/M2 MacBook | One native external display | A second dock group cannot add a native stream. |
| Base M3 MacBook | Two with Apple’s closed-lid conditions | Use the exact Mac and macOS requirement. |
| M4/M5 or Pro/Max Mac with two native streams | Two through this dock | Use one output from each Mac group. |
| Windows TB4 / USB4 + DP 1.4 HBR3 with DSC | Up to four | GPU topology, active internal display and combined modes still matter. |
| Windows Thunderbolt 3 | Up to two with two host streams; otherwise one | A Thunderbolt logo alone does not establish two streams. |
| Windows USB-C DP Alt Mode | HBR3+DSC: up to dual 4K60; HBR3 without DSC: dual 1440p60; HBR2: dual 1080p60 or single 4K30 | USB may also fall to 5Gbps; ordinary USB-C without DP Alt Mode supplies no native video. |
Plugable TBT4-UDZ: host, output groups and charging · Plugable TBT4-UDZ: display groups and host qualifications
Functional connection map
- Mac group 1choose HDMI or DisplayPort→external display 1
- Mac group 2choose HDMI or DisplayPort→external display 2
- Windows groups 3 / 4HDMI or DisplayPort where the host/table permits→optional displays 3 / 4
- PowerDock supply → up to 98 W certified host delivery
- Data2.5 GbE plus USB; rear USB-C provides 10Gbps accessory data and up to 7.5 W
- CablesOne suitable HDMI or DisplayPort cable per monitor
What is included and what you still need
| Item | Status | Why it matters |
|---|---|---|
| Host and power | Included: 1 m 40Gbps Thunderbolt 4 cable, dock supply and AC cable | Use the front computer-facing port; an arbitrary USB-C cable may not preserve the required link. |
| Monitor cables | Bring one suitable HDMI or DisplayPort cable per monitor | Plugable’s standard in-box list does not include monitor cables. |
| Display software | No DisplayLink or dock video driver | First-connect Thunderbolt/accessory approval can still be required; an optional Windows Ethernet driver is a network troubleshooting step only. |
| Operating system | Windows 10/11 or macOS 11+ | Plugable does not support this model on Linux or ChromeOS. |
Bring up a two-screen desk
- Power the TBT4-UDZ and connect the computer to the front host port with its intended Thunderbolt cable.
- Connect one monitor to HDMI or DisplayPort in group 1 and select that monitor input.
- Connect the second Mac monitor to one socket in group 2. On Windows, add other groups only when the exact host and mode table supports them.
- Choose an extended desktop and verify the requested mode on each display.
- Check sleep/wake, Ethernet, USB and charging separately before relying on the desk.
Recover by the observed split
| What works | Next check | Expected outcome |
|---|---|---|
| USB/Ethernet, but no display | Confirm the computer is on the front host port; test one known-good monitor/cable in group 1. | A supported host enumerates one native display. |
| One Mac display only | Move the second screen to group 2; recheck the Mac’s native count and lid conditions. | Two independent desktops only when the Mac supports them. |
| Each display works alone | Lower to a documented combined mode and reconnect one group at a time. | Separates a combined-mode limit from a failed cable. |
| White dock light | Power is present but no active host link; recheck the front host port, supplied cable and OS accessory approval. | A recognized host changes the light to green. |
| Green dock light; one branch fails | The host link is active; isolate that display, USB or network path instead of changing AC power. | A branch-specific fault stays separated from host-link failure. |
| Displays work, charging is short | Compare the laptop requirement with 98 W certified delivery; use its charger too if needed. | Video/data remain while the laptop chooses a suitable power source. |
Plugable TBT4-UDZ: power and host-link light states · Plugable TBT4-UDZ: host, output groups and charging · Plugable: using the laptop charger with a charging dock
Ports and recovery steps that need strict scope
The rear USB-C connection provides up to 10Gbps accessory data and 7.5 W charging, but it is not a USB-C monitor output or downstream Thunderbolt port. A DisplayPort-to-HDMI route needs a directional active adapter. The dock documents 2.5 Gigabit Ethernet, but real network speed still depends on the host, cable and network. Do not treat any port count as measured throughput. Plugable TBT4-UDZ: host, output groups and charging
Do not update dock firmware routinely. Plugable limits its TBT4-UDZ updater to unresolved video flicker, wake/no-image or DisplayPort-specific detection after normal host-side updates and isolation; the updater requires an eligible Windows system. Plugable TBT4-UDZ: scoped video firmware recovery
Unknowns stay in the buying decision
HDR, exact host DSC availability, color depth, high-refresh combinations, enterprise network features and performance with an exact computer remain unverified here. The map is our functional explanation of published routes, not a photograph, manufacturer diagram or Connect Your Dock hardware test. Use the complete desk checklist before replacing working equipment.
Sources & scope
These instructions combine published references with our proposed diagnostic sequence. This setup has not been physically tested by Connect Your Dock. Manufacturer documents can change; use the exact model and scope linked below.
- Plugable TBT4-UDZ: host, output groups and charging
- Plugable TBT4-UDZ: display groups and host qualifications
- Plugable TBT4-UDZ: power and host-link light states
- Plugable TBT4-UDZ: scoped video firmware recovery
- Plugable: using the laptop charger with a charging dock