diff --git a/README.md b/README.md
index 1e04e57..ad86dfc 100644
--- a/README.md
+++ b/README.md
@@ -17,6 +17,9 @@ insert the PD blocker in line, between the power source (e.g. charger or host co
 it can be inserted between any two of these components, and will work the same.
 plug and receptacle can be either side, and it is reversible along the axis of the connectors (like normal USB-C connectors).
 
+PD communication is completely block.
+when over-voltage is detected (Vbus > 5.5V), power is cut and an OVP LED indicating the culprit side lights up.
+
 all other features of USB-C are preserved (e.g. USB2, USB3, USB4, SBU, orientation detection)
 some alternate modes requiring PD communication will not work anymore though.