It converts the data to be transmitted from electrical signals to optical signals for communication. The two ends of the optical fiber are respectively equipped with "optical cats" for signal conversion. Optical fiber is one of the most ideal transmission media in broadband network at present, which has the characteristics of large transmission capacity, good transmission quality, small loss and long relay distance. Optical fiber transmission adopts wavelength division multiplexing, that is, the data of multiple users in the cell are modulated into optical signals with different wavelengths and transmitted in one optical fiber. Broadband service self-help troubleshooting, simple and easy to operate, handling work order inquiry, ITV troubleshooting, broadband application and password service.