Fax machine is an office equipment that transmits paper documents through communication lines, with the core process of "scanning encoding transmission decoding printing". Divided into traditional telephone type, network type, etc., there are thermal, inkjet, laser and other technology types, which can be single function or integrated with printing, scanning and other functions. It can stably send and receive multiple pages of documents, adapt to scenarios such as no network and compliance, and is easy to operate but relies on consumables. Although its usage scenarios have shrunk, it is still irreplaceable in specific fields.