1. Make sure that the network between the computer and the switch is smooth (it can also be directly connected to the console interface).

2. Open the simulation program (secuerCRT) on the computer.

3. Select "Quick Link" on the secuerCRT program, and then select TELNET to access the switch to be connected.

4. Log in to the switch.

5. After entering the login name and password, enter the command "disbriefinterface" in the current interface to display the online status of the current device port. According to the port list information, UP stands for online and DOWN stands for offline. By refreshing the port information list by plugging and unplugging equipment lines, you can quickly judge which interface and which equipment line of the switch are online.