diff --git a/lib/CMakeLists.txt b/lib/CMakeLists.txt
index e4ed842..f420820 100644
--- a/lib/CMakeLists.txt
+++ b/lib/CMakeLists.txt
@@ -31,6 +31,7 @@
     receiver/sch.c
     misc_utils/bursts_printer_impl.cc
     misc_utils/extract_system_info_impl.cc
+    demapping/universal_ctrl_chans_demapper_impl.cc
     demapping/get_bcch_or_ccch_bursts_impl.cc
     decoding/control_channels_decoder_impl.cc
     decoding/cch.c
diff --git a/lib/demapping/universal_ctrl_chans_demapper_impl.cc b/lib/demapping/universal_ctrl_chans_demapper_impl.cc
new file mode 100644
index 0000000..ea9a06e
--- /dev/null
+++ b/lib/demapping/universal_ctrl_chans_demapper_impl.cc
@@ -0,0 +1,135 @@
+/* -*- c++ -*- */
+/* 
+ * Copyright 2014 <+YOU OR YOUR COMPANY+>.
+ * 
+ * This is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * This software is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this software; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <gnuradio/io_signature.h>
+#include "universal_ctrl_chans_demapper_impl.h"
+#include <gsm/gsmtap.h>
+
+namespace gr {
+  namespace gsm {
+
+    universal_ctrl_chans_demapper::sptr
+    universal_ctrl_chans_demapper::make(const std::vector<int> &starts_fn_mod51, const std::vector<int> &channel_types)
+    {
+      return gnuradio::get_initial_sptr
+        (new universal_ctrl_chans_demapper_impl(starts_fn_mod51, channel_types));
+    }
+
+    /*
+     * The private constructor
+     */
+    universal_ctrl_chans_demapper_impl::universal_ctrl_chans_demapper_impl(const std::vector<int> &starts_fn_mod51, const std::vector<int> &channel_types)
+      : gr::block("universal_ctrl_chans_demapper",
+              gr::io_signature::make(0, 0, 0),
+              gr::io_signature::make(0, 0, 0))
+    {
+    
+        d_timeslot=0;
+        for(int ii=0; ii<51; ii++)
+        {
+            d_starts_fn_mod51[ii]=0;
+            d_channel_types[ii]=0;
+        }
+        
+        std::vector<int>::const_iterator s;
+        std::vector<int>::const_iterator ch_type;
+        
+        for(s=starts_fn_mod51.begin(), ch_type=channel_types.begin();s != starts_fn_mod51.end(); s++)
+        {
+            if((*s > 0) and (*s < (51-4)))
+            {
+                for(int ii=0; ii<4; ii++){
+                    d_starts_fn_mod51[*s+ii] = *s;
+                    if(ch_type!=channel_types.end())
+                    {
+                        d_channel_types[*s+ii] = *ch_type;
+                    }
+                }
+                if(ch_type!=channel_types.end())
+                {
+                    ch_type++;
+                }
+            }
+        }
+        
+        
+        message_port_register_in(pmt::mp("bursts"));
+        set_msg_handler(pmt::mp("bursts"), boost::bind(&universal_ctrl_chans_demapper_impl::filter_ctrl_chans, this, _1));
+        message_port_register_out(pmt::mp("bursts"));
+    }
+
+    /*
+     * Our virtual destructor.
+     */
+    universal_ctrl_chans_demapper_impl::~universal_ctrl_chans_demapper_impl()
+    {
+    }
+    
+    void universal_ctrl_chans_demapper_impl::filter_ctrl_chans(pmt::pmt_t msg)
+    {
+        pmt::pmt_t header_blob = pmt::car(msg);
+        pmt::pmt_t content = pmt::cdr(msg);
+        gsmtap_hdr * header = (gsmtap_hdr *)pmt::blob_data(header_blob);
+        uint32_t frame_nr = be32toh(header->frame_number);
+
+        uint32_t fn_mod51 = frame_nr % 51;
+        uint32_t fn51_start = d_starts_fn_mod51[fn_mod51];
+        uint32_t fn51_stop = fn51_start + 3;
+        uint32_t ch_type = d_channel_types[fn_mod51];
+        header->sub_type = ch_type;
+
+        if(header->timeslot==d_timeslot){
+            if(fn_mod51>=fn51_start && fn_mod51<=fn51_stop)
+            {
+                uint32_t ii = fn_mod51 - fn51_start;
+                d_frame_numbers[ii] = frame_nr;
+                d_bursts[ii] = msg;
+            }
+            
+            if(fn_mod51==fn51_stop)
+            {
+                //check for a situation where some bursts were lost
+                //in this situation frame numbers won't be consecutive
+                bool frames_are_consecutive = true;
+                for(int jj=1; jj<4; jj++)
+                {
+                    if((d_frame_numbers[jj]-d_frame_numbers[jj-1])!=1)
+                    {
+                        frames_are_consecutive = false;
+                    }
+                }
+                if(frames_are_consecutive)
+                {
+                    //send bursts to the output
+                    for(int jj=0; jj<4; jj++)
+                    {
+                        message_port_pub(pmt::mp("bursts"), d_bursts[jj]);
+                    }
+                } 
+            }
+        }
+    }
+  } /* namespace gsm */
+} /* namespace gr */
+
diff --git a/lib/demapping/universal_ctrl_chans_demapper_impl.h b/lib/demapping/universal_ctrl_chans_demapper_impl.h
new file mode 100644
index 0000000..472b321
--- /dev/null
+++ b/lib/demapping/universal_ctrl_chans_demapper_impl.h
@@ -0,0 +1,48 @@
+/* -*- c++ -*- */
+/* 
+ * Copyright 2014 <+YOU OR YOUR COMPANY+>.
+ * 
+ * This is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * This software is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this software; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifndef INCLUDED_GSM_UNIVERSAL_CTRL_CHANS_DEMAPPER_IMPL_H
+#define INCLUDED_GSM_UNIVERSAL_CTRL_CHANS_DEMAPPER_IMPL_H
+
+#include <gsm/demapping/universal_ctrl_chans_demapper.h>
+
+namespace gr {
+  namespace gsm {
+
+    class universal_ctrl_chans_demapper_impl : public universal_ctrl_chans_demapper
+    {
+     private:
+      unsigned int d_starts_fn_mod51[51];
+      unsigned int d_channel_types[51];
+      unsigned int d_timeslot;
+      uint32_t d_frame_numbers[4];
+      pmt::pmt_t d_bursts[4];
+     public:
+      universal_ctrl_chans_demapper_impl(const std::vector<int> &starts_fn_mod51, const std::vector<int> &channel_types);
+      ~universal_ctrl_chans_demapper_impl();
+
+      void filter_ctrl_chans(pmt::pmt_t msg);
+    };
+
+  } // namespace gsm
+} // namespace gr
+
+#endif /* INCLUDED_GSM_UNIVERSAL_CTRL_CHANS_DEMAPPER_IMPL_H */
+