function modemListen()
    local messageHandlers = {
        LFT = executeTurnLeft,
        RHT = executeTurnRight,
        FWD = executeForward,
        BWD = executeBack,
        UP = executeUp,
        DWN = executeDown,
        DCT_UPW = executeDetctUpward,
        DCT_DWD = executeDetctDownward,
        DCT_FWD = executeDetctForward,
        USE_FWD = executeUseForward,
        CHK_SL1 = getInventoryInfo_SLOT1,
      }

    modem.open(5)
    executed = false
  _, _, from, port, _, msg = event.pull(0.05,  "modem_message")
 if msg ~= nil then
  message = msg
  if message == "LFT" and not executed then
    executeTurnLeft()
    message = " "
  end
  if message == "RHT" and not executed then
    executeTurnRight()
    message = " "
  end
  if message == "FWD" and not executed then
    executeForward()
    message = " "
  end
  if message == "BWD" and not executed then
    executeBack()
    message = " "
  end
  if message == "UP" and not executed then
    executeUp()
    message = " "
  end
  if message == "DWN" and not executed then
    executeDown()
    message = " "
  end
  if message == "DCT_UPW" and not executed then
    executeDetctUpward()
    message = " "
  end
  if message == "DCT_DWD" and not executed then
    executeDetctDownward()
    message = " "
  end
  if message == "DCT_FWD" and not executed then
    executeDetctForward()
    message = " "
  end
  if message == "USE_FWD" and not executed then
    executeUseForward()
    message = " "
  end
  if message == "CHK_SL1" and not executed then
    getInventoryInfo_SLOT1()
    message = " "
  end
 else
    message = " "
 end
 os.sleep(0.0)
end