IOGear GUD3C03 Quick Start Manual Download Page 3

FAQ

Hardware Installation

3

Operating System

video resolution

MONITOR CONFIGURATION

Single Monitor

Dual Monitor

Laptop

Laptop

Laptop

USB-C

Thunderbolt 3

A

B

A

B

A

B

HDMI

Up to 3840 x 2160@30 Hz 

mDP

Up to 3840 x 2160@30 Hz 

VGA

Up to 1080P@60 Hz 

Windows 10 / Chrome OS / 

Mac OS X

Windows 10 / Chrome OS /

Mac OS X

Windows 10 / Chrome OS /

Mac OS X

Windows 10 / Mac OS X

Windows 10 / Mac OS X

Windows 10 / Mac OS X

USB-C

Thunderbolt 3

A

B

C

HDMI

Laptop

Laptop

Mini DisplayPort

A

B

B

HDMI Mini DisplayPort

Windows 10

Windows 10

Not Avaliable

Chrome OS / Mac OS X

Windows 10

Windows 10 / Mac OS X

Up to 1080P@60 Hz 

Up to 1080P@60 Hz 

Why do I have no display when the dock is connected?

The USB-C port in your host laptop needs to support USB-C DisplayPort 

Alternative Mode (DP Alt-Mode) for video viewing capability, otherwise the 

docking station can only act as a data / Ethernet hub.

I have the dock connected with HDMI and MiniDP, but when I plug in  

the VGA, only VGA works?  Why? 

HDMI and Mini DisplayPort (MiniDP) are digital signals, but VGA is analog signal.  

The dock can only support one type of signal at a time. Therefore, HDMI and 

MiniDP will work simultaneously, but VGA will work by itself.   

Can HDMI and VGA work together?

No. HDMI and VGA ports will not function simultaneously as they are two different 

signal types. HDMI is digital signal, and VGA is analog signal. Only one type of 

video signal can be supported at a time.

Can MiniDP and VGA work together?

No. MiniDP and VGA ports will not function simultaneously.  

  

Can I use a USB-C video adapter with this dock?  

No. Video adapter converting from MiniDP, HDMI, or VGA to other type of video 

interface will not work with this docking station. 

When I connect to an Apple laptop, I can’t extend the display of my 

desktop, why?

Apple’s Mac OS X does not support multiple display extension when on a USB-C 

platform and/or connecting to a USB-C peripheral. USB-C Macbook with macOS 

X 10.13.3 will only support one external display. USB-C Macbook with macOS X 

10.13.4 will support two external displays in mirror mode. Thunderbolt 3 Macbook 

will support two external displays.  

Why does the Ethernet connection not working on the docking 

station for my Apple laptop?

Please check your Networking Preference setting (Apple menu > System 

Preference > Network. The default Interface might set to Thunderbolt Bridge. 

Click Add button “+” at the bottom of the list at the left. Click the Interface pop-up 

menu, choose the “USB 10/100/1000 LAN” as network interface and create a new 

connection.

Can the dock charge my laptop?

No. The dock does not provide power to the connected computer or laptop.  In 

order for the connected computer or laptop to get charged, the computer needs to 

be USB-C Power Delivery compatible and the dock needs to be connected to an 

external USB-C AC power adapter.  

Can I use a bigger capacity AC power adapter with the dock to 

charge my laptop?

Yes. You may use any available USB-C AC power adapter with the dock to charge 

your laptop. When the USB-C AC power adapter is plugged into the docking 

station, the docking station will consume maximum of 15W power when all ports 

are connected and streaming data. The remaining power capacity will then be 

directed to the connected laptop, with the maximum of 45W power.   

Will this dock work when plugging into a Thunderbolt 3 port?

Yes, it will. The dock works when plugging into a Thunderbolt 3 port on your 

computer. However, due to the supporting features by the operating systems, the 

results will be different. For instance, Mac OS X supports only single display 

extension when using a USB-C peripheral, but Windows OS can support multiple 

display extensions.  

Will this dock work when plugging into a Thunderbolt 2 port?

No it will not. The dock will only function when plugging into a USB-C port or 

Thunderbolt 3 port. Please connect the docking station to your computer using the 

tethered cable. The particular port on the docking station is not compatible with 

Thunderbolt 2, but only Mini DisplayPort.  

Will the dock work with Apple Super Drive?

No. The dock does not work with Apple Super Drive. The SuperDrive requires a 

direct connection.    

How many external hard drives can be connected to the dock?

Just one. The external hard drive must be connected to the USB port marked with 

“BC 1.2” or Lightning logo. This USB port supports maximum of 1.5A power and 

will be able to provide enough power to the external hard drive device. 

My hard drive does not work when connected to the dock. Why?

Please make sure the external hard drive is connected  to the USB port marked 

with “BC 1.2” or Lightning logo. This USB port supports maximum of 1.5A power 

and will be able to provide enough power to the external hard drive device.

Will this dock work with a Thunderbolt 2 display?

No. This dock’s Mini DisplayPort does not support Thunderbolt 2 display.  

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