When working with any terminal or tablet that is a stationery terminal, it more than likely will be hardwired connected via Ethernet. Ethernet is cable that carries an electric signal that moves data from one computer to the next. It is generally more stable than Wi-Fi since it does not have to deal with all the wireless interference and congestion. We choose to use this to ensure higher up-times and stability. With that being said there will be some scenarios where you may have to troubleshoot the Ethernet cable. Let's go over what a healthy Ethernet connection looks like below. For all intents and purpose moving forward, we will refer to terminals/tablets as computers.
As you can see above, there are two LED lights in the port in which an Ethernet will be plugged into. Generally these LED lights will be on the port, it may be both LED, it may only be one. Sometimes in the case of the TP-Link they may put the LED status light in a different area of the box separate from the port. The Top-Left Link LED lets you know if the cable is physically connected to two computers as well as receiving a signal, this LED will stay solid. The Top-Right Activity LED lets you know if they are Data Packets flowing through, this LED will blink as Data is passing through. Let me go over a few scenarios of lights to know which troubleshooting step to take...
Solid Link, Blinking Activity: Healthy cable
Solid Link, No Blinking Activity: Physically connected but no Data passing through, possibly ISP issue or power-cycle/unplug/replug the cables to reseat them in case loose connection.
No Link, No Activity: Cable is either not seated properly or the computers are not turned on. Please re-seat and make sure computers are on, or the switch it is connecting is on (TP-Link Switch). If the switch is not on, please powercycle or move the power plug to a different outlet. If the switch powers on but the network does not work, replace the cable. If the switch does not power on, replace the switch. If it is plugged into a wall jack, the wall jack may need to be repaired which will require the location to call in an electrician as we don't perform that kind of cable work.
Now you are a master of the Ethernets!