diff --git a/src/gsm/lapdm.c b/src/gsm/lapdm.c
index 99099d1..8ec942f 100644
--- a/src/gsm/lapdm.c
+++ b/src/gsm/lapdm.c
@@ -23,6 +23,7 @@
 
 /*! \addtogroup lapdm
  *  @{
+ *  \brief GSM LAPDm (TS 04.06) implementation
  */
 
 /*! \file lapdm.c */