diff --git a/Expanding-Sonoffs.md b/Expanding-Sonoffs.md
index 45a66388..d41822a4 100644
--- a/Expanding-Sonoffs.md
+++ b/Expanding-Sonoffs.md
@@ -128,7 +128,7 @@ Internal pull-up/-down resistors
 GPIO 0-15 all have a built-in pull-up resistor, just like in an Arduino. GPIO16 has a built-in pull-down resistor.
 
 ### PWM
-Unlike most Atmel chips (Arduino), the ESP8266 doesn’t support hardware PWM, however, software PWM is supported on all digital pins. The default PWM range is 10-bits @ 1kHz, but this can be changed (up to >14-bit@1kHz).
+Unlike most Atmel chips (Arduino), the ESP8266 doesn’t support hardware PWM, however, software PWM is supported on all digital pins. The default PWM range is 10-bits @ 1kHz, but this can be changed (up to >14-bit@1kHz). Check [Restrictions](https://github.com/arendst/Sonoff-Tasmota/wiki/Expanding-Sonoffs#restrictions).
 
 ### Analog input
 The ESP8266 has a single analog input, with an input range of 0 - 1.0V. If you supply 3.3V, for example, you will damage the chip. Some boards like the NodeMCU have an on-board resistive voltage divider, to get an easier 0 - 3.3V range. You could also just use a trimpot as a voltage divider.