Combo interface is also called photoelectric multiplexing interface, which is composed of two Ethernet ports (one optical port and one electrical port) on the switch panel. The combo electrical port and its corresponding optical port are logically photoelectric multiplexed. The user can choose one of them according to the actual networking situation, but the two cannot work at the same time.
Simply speaking, the photoelectric multiplexing port is an interface that can be used as an electrical port or an optical port. The network port is the electrical port, and the optical module is connected to the optical fiber to be the optical port. However, the photoelectric multiplexing port cannot use the optical port after using the electrical port, and cannot use the electrical port after using the optical port.