When the device is connected to the computer, the power and mass storage connection are established. In this state, the display only shows the 'USB symbol' and the battery charging icon. This means the device will charge and data transfer from the VoiceTracer to the PC is allowed, and will not allow any recording.
In order to record with the VoiceTracer and at the same time charge the device from the PC, you need to press and hold the 'Record button' for at least 2 seconds to terminate the mass storage connection.