Generally, in the network cabling, outdoors (connection between buildings) use fiber termination box, while indoors (inside buildings) use Ethernet twisted pair cables. Then, how to convert the transmission media between the outdoor optical network and the indoor Ethernet network? And what devices are used in the connection? What roles do they play? How about the relationship between them? The answers are as following. Firstly, the mainly used devices are fiber termination box, fiber optic patch cable, fiber pigtail, and optical transceiver module, etc. Fiber Termination Box: This is a terminal protection box for the splicing of fiber optic cable and pigtail. Fiber termination box is a cable end fitting. Its two ends are fiber optic cables and pigtails, the equivalent is to be split into a single fiber optic cable equipment. Fiber termination box is used to terminate fiber optic cable, and connect the core to pigtails. The access fiber cable can have multi cores, for example, a 4-core cable (cable has four cores), through termination box, you can splice this optical cable to a maximum of four fiber pigtails, that leads out of 4 fiber patch cables. Fiber Pigtail: The connector at one end and the other end is a cable core breakage. It is also known as swine pigtail cable terminal box to the device that is used for the connection between the optical fiber. Often divided into single-mode or multi-mode fiber pigtail, single fiber or dual fiber, transmission distance, as well as pigtail interface type. Commonly used in fiber optic devices currently on the market, pigtail interface types are generally include FC, SC, LC, and ST four types. Usually, there are no pure fiber pigtails on sale, but we can cut the fiber patch cable from the middle, it then becomes two fiber pigtails. Pigtails for use in terminal box connect the fiber optic cable through the terminal box coupler (adapter) to connect pigtails and fiber patch cables. Fiber optic closure and fiber termination box are not the same. Fiber optic closure is fully sealed and waterproof. but it can not fix pigtails. While fiber termination box is not waterproof, but the internal structure can fix fiber optic cables. Then, what is the difference between the fiber patch cable and fiber pigtail? Can the fiber patch cable be divided into two fiber pigtails? Only one end of fiber pigtail is an active connector, while fiber patch cables have active joints on both ends. There are many different interfaces require different couplers. Fiber patch cables can be used as a divided two pigtails.