Areca Thunderbolt T3U supports USB host from T3U but not T3. Please make sure you use correct cable, USB cable and thunderbolt cable have same form factor but they are not compatible, thunderbolt cable has a thunderbolt sign on the connector. You must use thunderbolt cable if you want connect T3U to thunderbolt host. T3U may not start up if you use USB cable to connect thunderbolt host. Regarding the USB link speed, please use USB link status tool to find out which link speed the T3U got. The link speed could be USB2 using Thunderbolt 3 cable even if the USB host is USB3 capable.
Tags: ARC-8050T3U, cable, USB-C