diff --git a/source/_integrations/modbus.markdown b/source/_integrations/modbus.markdown
index d60075a741a..448cd3c2e1d 100644
--- a/source/_integrations/modbus.markdown
+++ b/source/_integrations/modbus.markdown
@@ -24,7 +24,7 @@ ha_integration_type: integration
 
 [modbus](http://www.modbus.org/) is a communication protocol to control PLCs (Programmable Logic Controller) and RTUs (Remote Terminal Unit).
 
-The integration adheres strictly to the [protocol specification](https://modbus.org/docs/modbus_Application_Protocol_V1_1b3.pdf) using [pymodbus](https://github.com/pymodbus-dev/pymodbus) for the actual protocol implmentation.
+The integration adheres strictly to the [protocol specification](https://www.modbus.org/docs/Modbus_Application_Protocol_V1_1b3.pdf) using [pymodbus](https://github.com/pymodbus-dev/pymodbus) for the actual protocol implmentation.
 
 The modbus integration supports all devices adhering to the modbus standard. The communication to the device/devices can be serial (rs-485), TCP, or UDP connections. The modbus integration allows multiple communication channels e.g. a serial port connection combined with one or more TCP connections.