diff --git a/hotplug/span_config.d/50-asterisk b/hotplug/span_config.d/50-asterisk
index 2e7adbd..3b75899 100755
--- a/hotplug/span_config.d/50-asterisk
+++ b/hotplug/span_config.d/50-asterisk
@@ -1,5 +1,10 @@
 #! /bin/sh
 
+# This file, if installed under /usr/share/dahdi/span_config.d/ , will
+# attempt to add a newly-generated span to a running copy of Asterisk.
+# Asterisk has to be running (if not: it will pick the span on its
+# startup), and has to have the channels already configured.
+
 if [ "$ACTION" != 'add' ]; then
 	# Nothing to do here
 	exit 0