Bärbar USB 2.0-hubb med 4 portar och inbyggd kabel

Industrial USB hubs offered by StarTech.com require an external power supply that connects to the terminal block on the hub. StarTech.com does not sell power supplies for these hubs and a power supply must be provisioned separately.

To select a power supply, you need to determine the maximum power requirements (wattage) of the hub.

The equation you should use to determine the power requirements is P = 5 * I * N, where the following is true:

• P is the power in watts.
• 5 is the voltage of the USB port.
• I is the current of the USB port in Amps.
  • I = 0.5 A for USB 2.0.
  • I = 0.9 A for USB 3.0.
• N is the number of USB ports.

For example, a four-port USB 3.0 hub's maximum power requirement is P = 5 * 0.9 * 4. Therefore, the minimum wattage of the power supply for the four-port USB 3.0 hub is 18 watts.

When you determine the power requirements of the hub, you can choose a power supply. The following criteria must be met when you select the power supply:

• The voltage must be within 7 to 24 or 7 to 40 Volts DC, depending on the specifications of the USB hub.
• The power supply must convert AC to DC (no AC output).
• The power rating is equal or greater to the requirements of the hub.

Most power supplies come with a rating in volts (V) and amps (A). To determine the current in amps, use I = P / V, where the following is true:

• I is the current of the power supply.
• P is the calculated power of the hub.
• V is the chosen voltage of the power supply (between 7 to 24 or 7 to 40 volts).

For example, if a hub requires 18 W and you choose a 12 V power supply, the current of the power supply would be I = 18/12, I = 1.5A.

Power supplies are sold by a number of online distributors and resellers. StarTech.com does not provide any official recommendations for distributors or resellers.

When you troubleshoot issues with a USB hub, there are some quick tests that you can complete to rule out potential problems. You can test to make sure that the following components are working correctly and are not the source of the issue:

• USB A-to-B cable

• Computer USB port

• USB peripheral(s)

To test your setup components, try the following:

• Use the USB cable and USB peripheral(s) in another setup to see if the problem is with the components or the setup.

• Use a different USB cable, USB port, and USB peripheral in your setup to see if the problem persists. Ideally, you should test a component that you know works in another setup.

When you test your cables, it is recommended that you do the following:

• Test each cable individually.

• Use short cables when you are testing.

When you test the hub, make sure that you do the following:

• If a power adapter is included, provide power to the USB hub.

• Attach a USB peripheral. The USB hub will not appear in any hardware listings on your system, but USB devices do appear when they are connected.

• Install the drivers for the USB peripheral.

• Install the latest drivers for the USB controller and motherboard chipset.

Note: No drivers or software are required for the USB hub to work with your operating system. The USB hub works independently of software and works with any operating system.

When testing your USB peripherals, make sure that you do the following:

• If required, attach external power.

• Confirm that the peripheral works on a standard USB port.

If the USB peripheral(s) can be detected on a standard USB port and not on the hub, do the following:

• Use a new USB A-to-B cable.

• Test your setup using basic USB peripherals, such as a keyboard or mouse.

• Test using another USB port.

If the USB device does not work after your computer has been in extended hibernation, it is likely that Windows has automatically turned off the USB Root hub to save power. 

The steps below outline how to configure the USB root hub to stay on during hibernation, to prevent this from happening.
 

Windows 10 / 8

1. On your keyboard, press the Windows key + X and select Control Panel.
2. Click Hardware and Sound, then click Power Options.
3. Click Change plan settings for the plan you want to change.
4. Click Change advanced power settings.
5. Click the plus sign (+) next to “USB settings” and “USB selective suspend setting” to expand the options and change the setting to Disabled.
6. Click OK to apply the setting.

Note: You may need to disconnect and re-connect your USB device after applying these settings to re-establish the connection.

Windows 7 / Vista

1. Click the Start button and select Control Panel.
2. Click Hardware and Sound, then click Power Options.
3. Click Change plan settings for the plan you want to change.
4. Click Change advanced power settings.
5. Click the plus sign (+) next to “USB settings” and “USB selective suspend setting” to expand the options and change the setting to Disabled.
6. Click OK to apply the setting.

Note: You may need to disconnect and re-connect your USB device after applying these settings to re-establish the connection.

Windows XP

1. On your desktop, right-click the My Computer icon and select Properties.
2. Click the Device Manager tab.
3. Expand Universal Serial Bus controllers by clicking the arrow to the left of it.
4. Right-click the first USB Root Hub device and select Properties.
5. Click the Power Management tab.
6. Clear the box next to Allow the computer to turn off this device to save power.
7. Click OK to apply the setting.
8. Repeat steps 4-7 for any remaining devices in the Universal Serial Bus Controllers section with “Root Hub” in the name.

Note: You may need to disconnect and re-connect your USB device after applying these settings to re-establish the connection.