The fiber optic connector is a universal passive device. For the same type of fiber optic connector, it can be used in any combination and can be used repeatedly. Therefore, the additional loss introduced is generally less than 0.2 dB. People who are not always in contact with fiber optics may mistake the fiber optic connectors of GBIC and SFP modules for the same type, but they are not. The SFP module is connected to the LC fiber connector, and the GBIC is connected to the SC fiber optic connector. Below we will detail the various fiber optic connectors in the communication network, and also show some fiber optic connectors that are rarely touched.