Understanding the Control Port on Acroname Hubs

2025 April 10

 We sometimes get questions about how to use the control port on our industrial USB Hubs.  Each hub works a little differently:

USBHub2x4

USBHub2x4 front panel

USBHub2x4 is our compact two-host, four-port USB 2.0 hub.

  • No control port
  • Defaults to automatic host switching between  host ports (port 0 priority)
  • The active host controls the hub

If the initial host computer tells the hub to switch hosts, it loses its connection and can’t communicate with the hub. The new host would have to tell the hub to switch back.

USBHub2x4 with 2 hosts

USBHub3+

USBHub3+ is our high-density two-host, eight-port (plus one downlink port) USB 3.2 Gen 1 5 Gbps Hub

USBHub3+ back panel
  • Has control port
  • Defaults to automatic host switching between  host ports (port 0 priority)
  • Active host or control port can manage the hub:
    • When control port is connected, the hub can only be managed through the control port

This enables a few control configurations:

  • Dedicated control PC connected to the control port
     

    Dedicated Control PC

  • No control port connection: active host manages the hub

    No Control port, 2 hosts

  • One of the hosts is also connected to the control port, maintaining control even when switching to the other host.
     

    Host and Control port connection

USBHub3c

USBHub3c front panel

USBHub3c is an industrial 6-port USB-C hub with the ability to configure any numbered port as a host connection.  All ports including the control port can source or sink up to 100 W.

  • Has control port
  • Defaults to host on port 0
  • Automatic host switching mode enables on host connection on any of the 6 ports, lowest number port priority.
  • Active host or control port can control the hub:
    • When control port is connected, the hub can only be managed through the control port

Configurations:

  • Dedicated control PC connected to the control port:
     

    USBHUb3c with dedicated control PC

  • Active Host manages the hub:
     

    USBHub3c without control port (Host control only)

  • One of the hosts is also connected to the control port, maintaining control even when switching to another host:
     

    USBHub3c with Host 0 connected to both control and host ports

Which configuration to use?

  • Don't need host switching: host-only connection
  • Host switching, host needs to control hub functions: host and control connection
  • Control computer doesn't need to be a host: dedicated control PC

 

 


 

 

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