diff --git a/grc/gsm_block_tree.xml b/grc/gsm_block_tree.xml
index e32121c..0a55b8d 100644
--- a/grc/gsm_block_tree.xml
+++ b/grc/gsm_block_tree.xml
@@ -36,6 +36,8 @@
     <cat>
       <name>Utilities</name>
       <block>gsm_bursts_printer</block>
+      <block>gsm_burst_sink</block>
+      <block>gsm_burst_source</block>
       <block>gsm_extract_system_info</block>
       <block>gsm_controlled_rotator_cc</block>
       <block>gsm_controlled_const_source_f</block>