Why can't I link the router with a computer on campus, but I can plug in the network cable directly? If yes, how to set up the router?

Broadband modems (cats) such as Huawei and Tianyi are all made by routers. You need to use the super password to turn on the router function before you can connect the router device.

The default super administrator password is

User name: telecomadmin

Password: nE7jA%5m