diff --git a/grc/gsm_block_tree.xml b/grc/gsm_block_tree.xml
index d5b822b..46f96ff 100644
--- a/grc/gsm_block_tree.xml
+++ b/grc/gsm_block_tree.xml
@@ -22,6 +22,7 @@
     <cat>
       <name>Logical channels demapping</name>
       <block>gsm_universal_ctrl_chans_demapper</block>
+      <block>gsm_tch_f_chans_demapper</block>
     </cat>
     <cat>
       <name>Decryption</name>