Abstract: The invention concerns a system for monitoring the movement of goods inwa and/or outwards with the aid of characteristic markings, such as a bar code which is scanned by a reading pen. Each reading pen is connected by a terminal which has a display and keys for giving special signals by flexible connecting wires. Each terminal is connected via an infrared beam with a so-called converter and this is connected via connecting wires with a control center and a processor as well as a memory. The reading pen contains no electronic components, as small proportion of these are contained in the terminal while the by far greater proportion is contained in the control center with the related processor and memory.The signals from the reading pen transmitted to the control center and passed on to the processor and memory are also transmitted back to the terminal concerned where they appear in a display so that the person operating the lightweight reading pen can check them.