Update README.md

README.md

@@ -5,4 +5,4 @@ Original code at: https://code.google.com/archive/p/cec-arduino/ (c) Phil Burr a
 
 This is an Arduino library which implements the HDMI v1.3a CEC wire protocol which allows communication with HDMI CEC capable devices. A typical usage scenario would be a Home Theater PC environment which uses HDMI but does not support CEC. This would allow the HTPC to communicate with other HDMI CEC equipment.
 
-Note: many HDMI sinks also want +5V supplied on the hot-plug detect (HPD) pin before they start using the port (not shown in schematic).
+Note: many HDMI sinks also want +5V supplied on the hot-plug detect pin (HPD, pin 19) before they start using the port. The bold numbers in the schematic on the right correspond to the HDMI pin numbers where the signals should be connected (see also https://en.wikipedia.org/wiki/HDMI).