Extender Charging

Extender is shipped with a charged battery as per regulatory requirements. We recommend customers fully charge their Extender before first use to provide the best user experience. If you are only using it in pass-through mode this is less important.

The Extender will charge when it is connected to a PC or to a DCP (Dedicated Charging Port) and it will automatically select one of 3 different battery charging currents depending on where it is connected. The USB 2.0 standard specifies that a device should not draw more than 100mA until the port is enumerated and then limited to 500mA. A dedicated charger such as one designed for a phone can supply 1A. The following table details how this selection will be performed.

Device connected

Charging current

PC but USB enumeration not completed


PC and USB enumeration completed


Dedicated Charge Port

1 A

Headset power and charging

When a headset is connected, Extender will supply power via the USB connector to ensure that the battery in the headset is not depleted. In order to save power, Extender will turn off power to the headset USB connector as described by the following table. It is possible to charge a headset and Extender at the same time if they are daisy chained together, however it will be quicker to charge the headset connected directly due to limited current on a USB port.

Extender status

Headset USB 5V status





It is important to turn on Extender first before connecting the headset because when Extender is off it is not be able to detect a headset connection.

If Extender is turned on and the headset is connected, Extender will set the charging current for the headset battery by sending the appropriate command through the USB connection. The charging current of the headset depends on the state in which Extender is operating as illustrated by the following table.

Extender state

Headset charging current

Connected to neither PC nor DCP

No charging. The Extender will only provide the current that is necessary to operate the headset but not charge the battery.

Connected to PC

Low charging current

Connected to DCP

High charging current

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