Status LEDs are the LEDs on the device that display its state.
Those LEDs are defined in a template or module using Led1, Led2, Led3 or Led4 (or Led1i, Led2i, Led3i or Led4i) and additionally using LedLink or LedLinki (LedLink was introduced in version 6.5.0.12). It is not recommended to assign Led<x> and Led<x>i with the same <x> number. Prior to version 6.5.0.12, Tasmota only supported up to two LED components to indicate the power state of the relay(s), and the Wi-Fi/MQTT connectivity status.
It is possible to wire in your own LED and assign it as any of the above mentioned but that's outside the scope of this article.
If only one LED is configured, it serves both purposes; the link status LED and/or the LED that indicates the power state of the relay(s). If more than one LED component is defined, Led1/Led1i will act as the Wi-Fi/MQTT status LED and the next defined LED (e.g., Led2/Led2i) will act as the LED that indicates the power state of the relay(s). This is the default behavior. Configuring a GPIO as an LEDLink/LEDLinki component changes this behavior.
For example, on a Sonoff Basic the green LED is used as the link status LED. Once the device connects, the LED is used to indicate the relay's power status.
Link status LED
Link status LED shows the network state, more specifically the Wi-Fi and MQTT connection status.
It blinks if the device is not connected to your Wi-Fi AP and MQTT broker (if MQTT is enabled). You can change this behaviour with LedState or turn it off with SetOption31.
Power status LED
Power status LED shows the power status of relay component(s). LedMask determines which relay(s) are associated with the power status LED. This behavior can be modified with the LedState command. The LED is turned off by default when the relay is OFF and turned on when the relay switches ON.
Depending on the device design, some LEDs are connected to the same GPIO as the relay. Those cannot be independently controlled since they have to follow the relay state.
If you have more than one LED wired independently and you want it to show the power state of the relay, you must assign an LedLink GPIO.
Using LedLink
LedLink / LedLinki was introduced with Tasmota version 6.5.0.12. It is used to assign the link status LED. If your device does not have an LED for link status (or you want to use that LED for a different purpose), you can assign LedLink to an available free GPIO. When LedLink(i) is assigned, other LEDs are automatically linked to their corresponding relay and serve as that relay's power status LED - i.e., Led<x>(i) links to Relay<x>(i)
LedPower command
When you use LedPower you take over control of that particular LED and it stops being linked to its corresponding relay and being its power status LED.