diff --git a/grc/grgsm_uplink_downlink_filter.xml b/grc/grgsm_uplink_downlink_filter.xml
index d868752..65d852d 100644
--- a/grc/grgsm_uplink_downlink_filter.xml
+++ b/grc/grgsm_uplink_downlink_filter.xml
@@ -4,7 +4,7 @@
   <key>grgsm_uplink_downlink_filter</key>
   <category>GSM</category>
   <import>import grgsm</import>
-  <make>grgsm.uplink_downlink_filter($direction)</make>
+  <make>grgsm.uplink_downlink_filter()</make>
   <sink>
     <name>in</name>
     <type>message</type>