diff --git a/lib/tdm_ripper.cpp b/lib/tdm_ripper.cpp
index d4da6fd..b0915c5 100644
--- a/lib/tdm_ripper.cpp
+++ b/lib/tdm_ripper.cpp
@@ -1,9 +1,11 @@
 
 #include "tdm_ripper.hpp"
 
-tdm_ripper::tdm_ripper(std::string tdmfile, std::string tdxfile):
-  tdmfile_(tdmfile), tdxfile_(tdxfile), num_channels_(0), num_groups_(0),
-  channel_id_(0), inc_id_(0), units_(0), channel_name_(0), group_id_(0), group_name_(0),
+tdm_ripper::tdm_ripper(std::string tdmfile, std::string tdxfile, bool neglect_empty_groups):
+  tdmfile_(tdmfile), tdxfile_(tdxfile),
+  neglect_empty_groups_(neglect_empty_groups), num_empty_groups_(0),
+  num_channels_(0), num_groups_(0), channel_id_(0), inc_id_(0), units_(0),
+  channel_name_(0), group_id_(0), group_name_(0),
   num_channels_group_(0), channels_group_(0), channel_ext_(0), minmax_(0),
   byteoffset_(0), length_(0), type_(0), external_id_(0)
 {
@@ -97,11 +99,15 @@ void tdm_ripper::parse_structure()
   {
     if ( std::string(anode.name()).compare("tdm_channelgroup") == 0 )
     {
-      num_groups_++;
-      group_id_.push_back(anode.attribute("id").value());
-      group_name_.push_back(anode.child_value("name"));
       int numchann = count_occ_string(anode.child_value("channels"),"id");
-      num_channels_group_.push_back(numchann);
+      if ( numchann > 0 || !neglect_empty_groups_ )
+      {
+        num_groups_++;
+        group_id_.push_back(anode.attribute("id").value());
+        group_name_.push_back(anode.child_value("name"));
+        num_channels_group_.push_back(numchann);
+      }
+      if ( numchann == 0 ) num_empty_groups_++;
     }
   }
 
@@ -201,18 +207,15 @@ void tdm_ripper::parse_structure()
   // std::string keyinit("usi23258");
   // std::cout<<"xml test "<<xml_double_sequence_[xml_values_[xml_local_columns_[keyinit]]]<<"\n\n";
 
-  // check consistency of number of channelgroups
+  // check consistency of number of channel-groups
   int numgroups = count_occ_string(subtreedata.child("tdm_root").child_value("channelgroups"),"id");
-  if ( 0*numgroups == 0 ) assert( numgroups == num_groups_ );
+  assert( (neglect_empty_groups_ && numgroups == num_groups_+num_empty_groups_)
+       || (!neglect_empty_groups_ && numgroups == num_groups_) );
 
   // check consistency of number of channels
   assert( num_channels_ == (int)channel_id_.size()
        && num_channels_ == (int)channel_name_.size()
        && num_channels_ == (int)channels_group_.size() );
-
-  std::cout<<std::setw(25)<<std::left<<"number of channels:"<<std::setw(10)<<num_channels_<<"\n";
-  for ( int i = 0; i < num_groups_; i++ ) std::cout<<std::setw(25)<<std::left<<"group"<<std::setw(10)<<i+1<<std::setw(10)<<no_channels(i+1)<<"\n";
-  std::cout<<std::right<<"\n\n";
 }
 
 void tdm_ripper::list_channels(std::ostream& gout, int width, int maxshow)
diff --git a/lib/tdm_ripper.hpp b/lib/tdm_ripper.hpp
index d376d1f..b8152d3 100644
--- a/lib/tdm_ripper.hpp
+++ b/lib/tdm_ripper.hpp
@@ -23,6 +23,10 @@ class tdm_ripper
   // endianness (true = little, false = big)
   bool endianness_, machine_endianness_;
 
+  // evtl. neglect groups with no actual channels
+  bool neglect_empty_groups_;
+  int num_empty_groups_;
+
   // number/names/ids of channels, channelgroups and channels's assignment to groups
   int num_channels_, num_groups_;
   std::vector<std::string> channel_id_, inc_id_, units_, channel_name_;
@@ -56,7 +60,7 @@ class tdm_ripper
 
 public:
 
-  tdm_ripper(std::string tdmfile, std::string tdxfile = "");
+  tdm_ripper(std::string tdmfile, std::string tdxfile = "", bool neglect_empty_groups = true);
 
   void parse_structure();
 
diff --git a/main.cpp b/main.cpp
index 615eb1c..e8aa1ba 100644
--- a/main.cpp
+++ b/main.cpp
@@ -43,8 +43,8 @@ int main(int argc, char* argv[])
   // for ( auto el: channA ) std::cout<<el<<"\n";
   // std::cout<<"\n\n";
 
-  for ( int i = 3; i < 10; i++ )
-  // for ( int i = 0; i < ripper.num_channels(); i++ )
+  // for ( int i = 3; i < 10; i++ )
+  for ( int i = 0; i < ripper.num_channels(); i++ )
   // for ( int i = 11880; i < ripper.num_channels(); i++ )
   {
     ripper.print_channel(i+1,("data/channel_"+std::to_string(i+1)+"_"
diff --git a/setup.py b/setup.py
index 8b277f5..6a2c47d 100644
--- a/setup.py
+++ b/setup.py
@@ -9,7 +9,7 @@ extensions = Extension(
     library_dirs=["lib"],
     include_dirs=["lib"],
     language='c++',
-    extra_compile_args=['-stdlib=libc++','-std=c++11'],
+    extra_compile_args=['-stdlib=libc++','-std=c++11','-Wno-unused-variable'],
     extra_link_args=['-stdlib=libc++','-std=c++11'],
 )