---
title: "LED indicators"
description: "What the LEDs on TapHome Core and IO modules mean: boot, TapHome bus, LAN and cloud status, plus blink codes for errors and what to check."
url: "https://taphome.com/en/docs/setup/led-indications/"
language: en
lastmod: 2026-11-06
generator: hugo
ai:
topics: ["led-indicators","troubleshooting","taphome-core","io-modules","taphome-bus","error-diagnosis"]
questions: ["What do the LED indicators on TapHome Core mean?","Why is LED 2 blinking on my TapHome Core?","How do I know if my TapHome Core is connected to the cloud?","What does it mean when an IO module LED blinks once?","What does it mean when an IO module LED blinks twice?","How to identify which IO module I'm configuring in the app?","What voltage is required for IO modules?"]
---
# LED indicators
Overview of LED indicators on Core, their states and error states of IO modules.
Last updated: 2026-11-06
The LED indicators on the TapHome Core and on IO modules show whether the device has started, whether it communicates on the TapHome bus, and whether it is connected to the local network and the cloud. On the Core, LED 1 reports the system boot and bus communication, LED 2 the local network and LED 3 the cloud connection. On an IO module, the LED shows that the module is powered and communicates with the Core control unit, or signals an error by blinking 1x, 2x or 3x or by staying off. Use the tables on this page to find the cause of a given LED state and what to check.
## Status information
-  **LED 1**:
- Three blinks after power-on indicate system boot.
- Otherwise, it indicates the communication status with other modules on the TapHome bus.
-  **LED 2**:
- The system is running.
- Connection to the local network has been established.
-  **LED 3**:
- Connected to the cloud.
- Remote access is available.
## Error states
| LED 2 (LAN) | LED 3 (Internet) | Description |
|-------------|------------------|-------------|
|  |  | The system did not start |
|  |  | LAN cable is disconnected |
|  |  | The device has not been assigned an IP address |
|  |  | TapHome Core firmware is not running |
|  |  | TapHome Core firmware cannot connect to the cloud |
|  |  | The device has DNS configuration issues |
|  |  | The device cannot connect to the internet |
|  |  | TapHome Core firmware is running and connected to the cloud |
## LED indicators on IO modules
### Status information
| LED | Description |
|----------------|-------------|
|  | The device is powered and communicates with the Core control unit.
✅ All good. |
|  | The configuration window in the iOS or Android app for this module is currently open.
✅ This is how you can identify the module you are configuring and name it for future use. |
### Error states
| **LED** | **Description** | **Actions** |
|---------------|-----------------------------------------------------------|-----------|
| 
**1x** | The device is powered but receives invalid communication packets. | ❌ Check that the bus is properly connected.
❌ Check that terminals A and B are connected in the correct order.
❌ Check that a 100 Ohm termination resistor is placed at the end of the bus between A and B.
❌ Check that the device is connected to TapHome Bus conductors. Connecting TapHome to Modbus or another protocol will cause invalid packets, shown as 1 blink. |
| 
**2x** | The device is powered and has valid communication with the Core control unit, but messages are not addressed to this module. | ✅ Everything is ready, but the module has not been scanned (**Hardware → TapHome Bus → Find new devices**). |
| 
**3x** | The device is powered but does not receive any communication. | ❌ Check that the correct **BUS terminal** is enabled in **Hardware → TapHome Bus → Terminals**. |
| 
**Off** | The device is not powered or is not functioning correctly. | ❌ Check that there is a voltage of **24VDC** between the **+24V and GND terminals**. Tolerance is **±10%**. |
**See also** — [Bus Analyzer](https://taphome.com/en/docs/setup/bus-analyzer/), [Backup, restore, factory reset](https://taphome.com/en/docs/restore/).