diff --git a/extras/Interesting URL b/extras/Interesting URL
index 773b38d..bccbddd 100644
--- a/extras/Interesting URL	
+++ b/extras/Interesting URL	
@@ -1,2 +1,5 @@
 http://palsbo.com/pi/owfsslave.html
 	An interesting project covering both Arduino and OWFS aspect
+
+http://www.datastat.com/sysadminjournal/maximcrc.cgi
+	Address CRC calculator