diff --git a/DMRIds.dat b/DMRIds.dat
index c267b2f..c0c0637 100644
--- a/DMRIds.dat
+++ b/DMRIds.dat
@@ -1,3 +1,7 @@
+#
+# The format of the file is the DMR Id followed by the callsign
+#
+# ID    Call
 1112001 KI4ZWE
 1112002 WA4ECT
 1112003 PU2TAW