Equipment failure. The mobile Wi-Fi optical signal flashes red for a long time because the device itself has failed. At this point, you can try to restart the device or pull out the SIM card and insert it again. The full name of WiFi is WirelessFidelity, also known as 802. 1 1B standard. Its biggest advantage is its fast transmission speed, which can reach 1 1 Mbps. In addition, the effective distance is also very long, and it is also compatible with various existing 802. 1 1 DSSS devices. WiFi is a brand of wireless network communication technology, which is owned by Wi-Fi Alliance. Its purpose is to improve the interoperability between wireless network products based on IEEE802. 1 1+0 standard. The Wi-Fi Alliance was founded in 1999, then its name was Wireless Internet Compatibility Alliance (WECA), and it was officially renamed as Wi-Fi Alliance in 2002.