'Get the latest details from the device.'

def update(self):

    try:
        nad_status = self.nad_device.status()
    except OSError:
        return
    if (nad_status is None):
        return
    if nad_status['power']:
        self._state = STATE_ON
    else:
        self._state = STATE_OFF
    self._volume = self.nad_vol_to_internal_vol(nad_status['volume'])
    self._nad_volume = nad_status['volume']
    self._mute = nad_status['muted']
    self._source = nad_status['source']
