diff --git a/lib/imc_datatype.hpp b/lib/imc_datatype.hpp
index 1a041fd..5e32608 100644
--- a/lib/imc_datatype.hpp
+++ b/lib/imc_datatype.hpp
@@ -16,6 +16,7 @@ namespace imc
   typedef signed long int imc_Slongint;
   typedef float imc_float;
   typedef double imc_double;
+  // TODO remaining types are not yet supported
 
   class datatype
   {
diff --git a/lib/imc_objects.hpp b/lib/imc_objects.hpp
index 2fca2e9..325987e 100644
--- a/lib/imc_objects.hpp
+++ b/lib/imc_objects.hpp
@@ -8,7 +8,7 @@
 namespace imc
 {
   // start of group of keys (corresponds to key CK)
-  struct group_keys
+  struct keygroup
   {
     int version_;
     int length_;
@@ -25,6 +25,241 @@ namespace imc
     }
   };
 
+  // group definition (corresponds to key CB)
+  struct group
+  {
+    unsigned long int group_index_;
+    std::string name_;
+    std::string comment_;
+
+    // get info string
+    std::string get_info(int width = 20)
+    {
+      std::stringstream ss;
+      ss<<std::setw(width)<<std::left<<"group-index:"<<group_index_<<"\n"
+        <<std::setw(width)<<std::left<<"name:"<<name_<<"\n"
+        <<std::setw(width)<<std::left<<"comment_:"<<comment_<<"\n";
+      return ss.str();
+    }
+  };
+
+  // text definition (corresponds to key CT)
+  struct text
+  {
+    unsigned long int group_index_; // corresponding to group-index in CB block
+    std::string name_;
+    std::string text_;
+    std::string comment_;
+
+    // get info string
+    std::string get_info(int width = 20)
+    {
+      std::stringstream ss;
+      ss<<std::setw(width)<<std::left<<"group-index:"<<group_index_<<"\n"
+        <<std::setw(width)<<std::left<<"name:"<<name_<<"\n"
+        <<std::setw(width)<<std::left<<"text:"<<text_<<"\n"
+        <<std::setw(width)<<std::left<<"comment_:"<<comment_<<"\n";
+      return ss.str();
+    }
+  };
+
+  enum fieldtype {
+    realnumber = 1,       // 1
+    xmonotony,            // 2
+    xy,                   // 3
+    complexrealimag,      // 4
+    complexabsphase,      // 5
+    complexdbphase        // 6
+  };
+
+  // definition of data field (corresponds to key CG)
+  struct datafield
+  {
+    unsigned long int number_components_;
+    fieldtype fldtype_;
+    int dimension_; // corresponding to fieldtype \in {1,}
+
+    // get info string
+    std::string get_info(int width = 20)
+    {
+      std::stringstream ss;
+      ss<<std::setw(width)<<std::left<<"#components:"<<number_components_<<"\n"
+        <<std::setw(width)<<std::left<<"fieldtype:"<<fldtype_<<"\n"
+        <<std::setw(width)<<std::left<<"dimension_:"<<dimension_<<"\n";
+      return ss.str();
+    }
+  };
+
+  // definition of abscissa (corresponds to key CD1)
+  struct abscissa
+  {
+    double dx_;
+    bool calibration_;
+    std::string unit_;
+
+    // get info string
+    std::string get_info(int width = 20)
+    {
+      std::stringstream ss;
+      ss<<std::setw(width)<<std::left<<"dx:"<<dx_<<"\n"
+        <<std::setw(width)<<std::left<<"calibration_:"<<(calibration_?"yes":"no")<<"\n"
+        <<std::setw(width)<<std::left<<"unit:"<<unit_<<"\n";
+      return ss.str();
+    }
+  };
+
+  // start of component (corresponds to key CC)
+  struct component
+  {
+    int component_index_;
+    bool analog_digital_;
+
+    // get info string
+    std::string get_info(int width = 20)
+    {
+      std::stringstream ss;
+      ss<<std::setw(width)<<std::left<<"index:"<<component_index_<<"\n"
+        <<std::setw(width)<<std::left<<"analog/digital_:"<<(analog_digital_?"digital":"analog")<<"\n";
+      return ss.str();
+    }
+  };
+
+  enum numtype {
+    unsigned_byte = 1,
+    signed_byte,
+    unsigned_short,
+    signed_short,
+    unsigned_long,
+    signed_long,
+    ffloat,
+    ddouble,
+    imc_devices_transitional_recording,
+    timestamp_ascii,
+    two_byte_word_digital,
+    six_byte_unsigned_long
+  };
+
+  // packaging information of component (corresponds to key CP)
+  struct packaging
+  {
+    unsigned long int buffer_reference_;
+    int bytes_;
+    numtype numeric_type_;
+    int signbits_;
+    int mask_;
+    unsigned long int offset_;
+    unsigned long int number_subsequent_samples_;
+    unsigned long int distance_bytes_;
+
+    // get info string
+    std::string get_info(int width = 20)
+    {
+      std::stringstream ss;
+      ss<<std::setw(width)<<std::left<<"buffer-reference:"<<buffer_reference_<<"\n"
+        <<std::setw(width)<<std::left<<"datatype:"<<numeric_type_<<"\n"
+        <<std::setw(width)<<std::left<<"significant bits:"<<signbits_<<"\n"
+        <<std::setw(width)<<std::left<<"mask:"<<mask_<<"\n"
+        <<std::setw(width)<<std::left<<"offset:"<<offset_<<"\n"
+        <<std::setw(width)<<std::left<<"#subsequent-samples:"<<number_subsequent_samples_<<"\n"
+        <<std::setw(width)<<std::left<<"distance in bytes:"<<distance_bytes_<<"\n";
+      return ss.str();
+    }
+  };
+
+  // buffer description (corresponds to key Cb)
+  struct buffer
+  {
+    unsigned long int number_buffers_;
+    unsigned long int bytes_userinfo_;
+    // for every single buffer
+    unsigned long int buffer_reference_; // corresponds to buffer_reference_ in key CP
+    unsigned long int sample_index_;     // corresponds to index of CS key
+    unsigned long int offset_buffer_;    // number of bytes from beginning of CS key
+    unsigned long int number_bytes_;     // number of bytes in buffer
+    unsigned long int offset_first_sample_;
+    unsigned long int number_filled_bytes_;
+    unsigned long int time_offset_;
+    unsigned long int add_time_;         // start of trigger time = NT + add_time
+    bool user_info_;
+    bool new_event_;
+
+    // get info string
+    std::string get_info(int width = 20)
+    {
+      std::stringstream ss;
+      ss<<std::setw(width)<<std::left<<"#buffers:"<<number_buffers_<<"\n"
+        <<std::setw(width)<<std::left<<"bytes user info:"<<bytes_userinfo_<<"\n"
+        <<std::setw(width)<<std::left<<"buffer reference:"<<buffer_reference_<<"\n"
+        <<std::setw(width)<<std::left<<"sample index:"<<sample_index_<<"\n"
+        <<std::setw(width)<<std::left<<"offset buffer:"<<offset_buffer_<<"\n"
+        <<std::setw(width)<<std::left<<"buffer size:"<<number_bytes_<<"\n"
+        <<std::setw(width)<<std::left<<"offset sample:"<<offset_first_sample_<<"\n"
+        <<std::setw(width)<<std::left<<"#filled bytes:"<<number_filled_bytes_<<"\n"
+        <<std::setw(width)<<std::left<<"time offset:"<<time_offset_<<"\n"
+        <<std::setw(width)<<std::left<<"add time:"<<add_time_<<"\n";
+      return ss.str();
+    }
+  };
+
+  // range of values of component (corresponds to key CR)
+  struct range
+  {
+    bool transform_;         // 1 = true: yes, requires offset + factor, 0 = false: no
+    double factor_, offset_; // value = raw value * factor + offset
+    bool calibration_;       // 1 = true: calibration, 0 = false: no calibration
+    std::string unit_;
+
+    // get info string
+    std::string get_info(int width = 20)
+    {
+      std::stringstream ss;
+      ss<<std::setw(width)<<std::left<<"transform:"<<(transform_?"yes":"no")<<"\n"
+        <<std::setw(width)<<std::left<<"factor:"<<factor_<<"\n"
+        <<std::setw(width)<<std::left<<"offset:"<<offset_<<"\n"
+        <<std::setw(width)<<std::left<<"calibration:"<<(calibration_?"yes":"no")<<"\n"
+        <<std::setw(width)<<std::left<<"unit:"<<unit_<<"\n";
+      return ss.str();
+    }
+  };
+
+  // channel (corresponds to key CN)
+  struct channel
+  {
+    unsigned long int group_index_;  // corresponds to group-index in CB key
+    bool index_bit_;                 // true =  1: digital, false = 0: analog
+    std::string name_;
+    std::string comment_;
+
+    // get info string
+    std::string get_info(int width = 20)
+    {
+      std::stringstream ss;
+      ss<<std::setw(width)<<std::left<<"group-index:"<<group_index_<<"\n"
+        <<std::setw(width)<<std::left<<"index-bit:"<<index_bit_<<"\n"
+        <<std::setw(width)<<std::left<<"name:"<<name_<<"\n"
+        <<std::setw(width)<<std::left<<"comment:"<<comment_<<"\n";
+      return ss.str();
+    }
+  };
+
+  // rawdata (corresponds to key CS)
+  struct data
+  {
+    unsigned long int index_;  // starting from 1 in first CS block in file
+    // std::vector<unsigned char> rawdata_;
+    unsigned long int begin_buffer_, end_buffer_;
+
+    // get info string
+    std::string get_info(int width = 20)
+    {
+      std::stringstream ss;
+      ss<<std::setw(width)<<std::left<<"index:"<<index_<<"\n"
+        <<std::setw(width)<<std::left<<"(begin,end) buffer:"
+                                     <<"("<<begin_buffer_<<","<<end_buffer_<<")"<<"\n";
+      return ss.str();
+    }
+  };
+
   // origin of data (corresponds to key NO)
   struct origin_data
   {
@@ -43,38 +278,18 @@ namespace imc
     }
   };
 
-  struct info
+  // trigger timestamp (corresponds to key NT)
+  struct triggertime
   {
-    // timestamp of measurement
     std::string timestamp_;
-    bool valid_;
 
-    // device and software
-    std::string origin_;
-  };
-
-  struct abscissa
-  {
-    // name of entity
-    std::string name_;
-
-    // its unit
-    std::string unit_;
-  };
-
-  struct channel
-  {
-    // name of channel
-    std::string name_;
-
-    // unit of channel's measurement entity
-    std::string unit_;
-
-    // datatype of channel
-    imc::datatype daty_;
-
-    // entity measurement depends on, i.e. channel's abscissa (mostly time)
-    abscissa channel_xaxis_;
+    // get info string
+    std::string get_info(int width = 20)
+    {
+      std::stringstream ss;
+      ss<<std::setw(width)<<std::left<<"timestamp:"<<timestamp_<<"\n";
+      return ss.str();
+    }
   };
 
 }
diff --git a/lib/imc_raw.hpp b/lib/imc_raw.hpp
index ebd377d..c673a8f 100644
--- a/lib/imc_raw.hpp
+++ b/lib/imc_raw.hpp
@@ -31,9 +31,6 @@ namespace imc
     unsigned long int cplxcnt_;
 
     // collect meta-information, channel definition, etc.
-    imc::info imcinfo_;
-    imc::channel imcchannel_;
-    imc::abscissa xaxis_;
 
   public: