diff --git a/README.md b/README.md
index 9b08954..e8a00e2 100644
--- a/README.md
+++ b/README.md
@@ -18,6 +18,11 @@ https://github.com/mattthebaker/Smoothieware-CHMT
 In this approach the entire head unit will be bypassed. Ideally this could be accomplished by
 utilizing the existing IDC connector on the power/comm sub-board.
 
+# 'CAN Bus'
+Communication is done over the VP230 CAN Transceiver, though it doesn't look to be real CAN.
+Instead the STM32 USART1 is connected so it's doing Syncronous UART over CAN. So it's really
+just using the VP230 for differential signaling.
+
 # Reading
 
 https://www.eevblog.com/forum/manufacture/neoden-tm245p-teardown-and-upgrade/