According to USB Standards, USB Ports provide a voltage of 5 VDC ± 5%.
However, this voltage is only available under certain operating states of the computer.
If the computer is configured to go into “Standby”, “Sleep Mode” or “Hibernation”, (see the PC “Power Options Properties” Control Panel below, for example), the computer will not deliver a voltage to the USB Ports while in these power-preservation states.
This is a common condition in Laptop computers where battery power conservation is important. New computers are received with these settings enabled.
If the (Laptop) computer turns itself off because of a low Battery condition, it will not deliver power to the USB Ports. The computer states of “Standby”, “Sleep Mode” or “Hibernation” are independent settings that apply whether or not a Laptop computer itself is being charged through external power source.
USB Hubs depend on the host computer states to determine their voltage states.
USB Ports in a Laptop Docking Station require the Laptop be inserted and turned on to deliver voltage to the Docking Station USB Ports
Foremost, the computer must be awake to provide voltage to the USB Ports. If the USB Charging Cable does not have power indication, and the Headset does not have L.E.D. indication, There is no way of knowing if the Headset is being charged except by observing that the computer is awake.
If the Headset has charging indications (such as an L.E.D.) the Headset state should follow User Guide contents.
- It is best to turn the Headset off while being recharged – this reduces charge time while conserving energy.
- It is strongly advised to plan charging while the computer is in the awake state.
- Charge the Headset while not in use
- Change the computer “Standby”, “Sleep Mode” or “Hibernation” settings to allow for sufficient charge time according to the Headset User Guide or disable these settings completely.
- Make sure the computer has sufficient Battery power to stay awake while the Headset is charging
- Use an alternate means of charging such as an AC Linear or AC Switching Adapter Power Supply Unit , or the Headset System Base Charging Cradle (if applicable).