The event DataReceived is trigger by the serialport when have some veri to read, even Eof character is received. Tipicaly this event is used to get that data and start a process with it or store. For example, the serialport read a barcode and find it on the database. https://uydu-ayar-montaj00852.anchor-blog.com/6197051/bir-İnceleme-c-serialport-kullanımı