diff --git a/README.md b/README.md
index c92f75e..ac276be 100644
--- a/README.md
+++ b/README.md
@@ -4,7 +4,7 @@ Han port pinout:
 2. Data request (connect to 5V to enable)
 3. GND
 4. NC
-5. DATA (TX 115200 inverted)
+5. DATA (TX 115200 inverted open drain)
 6. GND
 
 Add pullup resistor between Pico RX pin and 3V3