## 2 State of the Art
This can be read, in turn, using a reflection effect from the \"laser\" emissions to the reader, which contains a photocell capable of converting the light into an electric current, obtaining an analogue signal that gives rise to a binary code, thus allowing the representation and transmission of information [5]. There are different barcode schemes, so the main differences are the type of characters (only numbers or alphanumeric characters), the amount of data, the length of the bars, and the representation of the information in terms of structure (which can be linear or two-dimensional). Furthermore, the choice of the type of code to be used in a given context is directly related to the needs of its application [10]. The constant evolution of technology and the growing need for companies and organisations to ensure that all data are included in the respective information flow, both externally (supply chain) and internally (organisation), to operate efficiently and consequently gain a competitive advantage in the market, presents barriers to the use of barcodes since the storage of information can become quite limited. Another barrier to applying this technology is the fact that barcode labels become damaged and unreadable. Humidity, dust, and high temperatures are generally characteristics of an industrial environment; these negatively affect the readability of the label [11]. Other disadvantages that can affect the profitability of the operation include the fact that there can be no obstacle between the reader and the barcode, which can lead to the impossibility of performing multiple readings, i.e., the reading must be performed label by label. There is also the disadvantage of a much slower reading speed compared to RFID technology [12]. Additionally, the barcode is no longer a technology for high-tech organisations, but an easy-to-use tool that can help any company that wants to use it simply. The cost of scanning devices and the amount of software required have decreased significantly [13]. Despite its limitations, barcode technology is easy to apply, which is demonstrated by its widespread use worldwide over many years, as well as its low acquisition and integration costs. These factors can, therefore, be decisive when deciding which automatic identification and data capture support technology to implement [14]. On the other hand, RFID is a technology that allows communication, identification, and data collection without any physical contact, but through radio-frequency waves. In the context under study, this technology can fulfil important functions with high profitability and operational flexibility, meaning that it can identify and collect data and location information in real time without any human intervention [15]. It can be used in various processes along the supply chain, with different impacts at each stage, and it should be noted that some of the most valuable applications in the context of supply circuits are as follows [6]:  
* Simplifying the monitoring of industrial production flows and stock management, since RFID helps to better localise products, updates in real time, and automates operations, thus increasing confidence in decision-making related to supplies;
* In the logistics process, this technology can make it possible to increase efficiency by speeding up the delivery of products or raw materials, automating the operations of receiving and dispatching goods, thus eliminating operations that do not generate value for the organisation, saving time for employees to focus on activities that add relevance to the business;
* Concerning the end customer, RFID can provide visibility and product information at any point in the supply chain automatically and assertively, thus improving the reliability of the information flow. An RFID system is essentially made up of one or more readers and tags. The first readers are responsible for reading the tags within their reading radius, so both components are systems for sending and receiving information and can be classified as \"transceivers\" [16].