WG3021 is a mechanical optical switching device that integrates timing control circuits and communication interfaces, with an operating keyboard and LED indicator lights for easy operation. This device operates in three wavelength windows of 1310nm/1490nm/1550nm, with low insertion loss, stable and reliable functionality, and high repeatability. The instrument has RS232 and USB interface functions, and can be sent instructions by a PC to complete all operations and controls, making it easy to form an automated measurement and control system together with other testing instruments. It greatly enhances the user experience process, making this instrument a powerful tool in many application scenarios, especially suitable for enterprises, factories, and research units to measure experiments, etc