diff --git a/protocol.txt b/protocol.txt
index 8bb52c3..6474158 100644
--- a/protocol.txt
+++ b/protocol.txt
@@ -27,6 +27,7 @@ Radio > Host : [8 Bytes]
 
 AD0 = Least significant byte of address
 AD1 = Most significant byte of address
+(Note: [AD1<<8 | AD0] mod 0x20 = 0)
 CKS = Regular additive checksum of the 32 data bytes