function Decoder(bytes, port) {
  // Decode an uplink message from a buffer
  // (array) of bytes to an object of fields.
  var value=(bytes[0]<<8 | bytes[1])&0x3FFF;
  var bat=value/1000;//Battery,units:V
  
  var door_open_status=bytes[0]&0x80?1:0;//1:open,0:close
  var water_leak_status=bytes[0]&0x40?1:0;
  
  var mod=bytes[2];
  var alarm=bytes[9]&0x01;
  
  if(mod==1){
    var open_times=bytes[3]<<16 | bytes[4]<<8 | bytes[5];
    var open_duration=bytes[6]<<16 | bytes[7]<<8 | bytes[8];//units:min
    if(bytes.length==10 &&  0x07>bytes[0]< 0x0f)
    return {
      BAT_V:bat,
      MOD:mod,
      DOOR_OPEN_STATUS:door_open_status,
      DOOR_OPEN_TIMES:open_times,
      LAST_DOOR_OPEN_DURATION:open_duration,
      ALARM:alarm
    };
  }
  else if(mod==2)
  {
  var leak_times=bytes[3]<<16 | bytes[4]<<8 | bytes[5];
  var leak_duration=bytes[6]<<16 | bytes[7]<<8 | bytes[8];//units:min
  if(bytes.length==10 &&  0x07>bytes[0]< 0x0f)
  return {
      BAT_V:bat,
      MOD:mod,
      WATER_LEAK_STATUS:water_leak_status,
      WATER_LEAK_TIMES:leak_times,
      LAST_WATER_LEAK_DURATION:leak_duration
  };
  }
  else if(mod==3)
  if(bytes.length==10 &&  0x07>bytes[0]< 0x0f)
  {
  return {
      BAT_V:bat,
      MOD:mod,
      DOOR_OPEN_STATUS:door_open_status,
      WATER_LEAK_STATUS:water_leak_status,
      ALARM:alarm
  };
  }
  else{
  return {
      BAT_V:bat,
      MOD:mod,
  };
  }
}