diff --git a/src/db/db/dbLayoutToNetlist.cc b/src/db/db/dbLayoutToNetlist.cc
index 5bac02736..3e54f5cac 100644
--- a/src/db/db/dbLayoutToNetlist.cc
+++ b/src/db/db/dbLayoutToNetlist.cc
@@ -262,6 +262,21 @@ void LayoutToNetlist::ensure_netlist ()
   }
 }
 
+void LayoutToNetlist::register_device_class (const DeviceClass &device_class)
+{
+  m_device_classes.push_back (device_class.clone ());
+}
+
+const DeviceClass *LayoutToNetlist::device_class_by_name (const std::string &name) const
+{
+  for (auto d = m_device_classes.begin (); d != m_device_classes.end (); ++d) {
+    if (d->name () == name) {
+      return d.operator-> ();
+    }
+  }
+  return 0;
+}
+
 void LayoutToNetlist::extract_devices (db::NetlistDeviceExtractor &extractor, const std::map<std::string, db::ShapeCollection *> &layers)
 {
   if (m_netlist_extracted) {
@@ -271,7 +286,34 @@ void LayoutToNetlist::extract_devices (db::NetlistDeviceExtractor &extractor, co
   ensure_netlist ();
 
   extractor.clear_log_entries ();
-  extractor.extract (dss (), m_layout_index, layers, *mp_netlist, m_net_clusters, m_device_scaling);
+
+  extractor.initialize (mp_netlist.get ());
+
+  //  Try finding the device class in the registered devices in the following order:
+  //  1.) Registered by the extractor during setup() (called by initialize())
+  //  2.) A corresponding device class already present in the netlist (done during initialize())
+  //  3.) Registered in LayoutToNetlist through register_device_class()
+  //  4.) The default class
+
+  if (! extractor.device_class ()) {
+    const db::DeviceClass *dc = device_class_by_name (extractor.name ());
+    if (dc) {
+      extractor.register_device_class (dc->clone ());
+    }
+  }
+
+  if (! extractor.device_class ()) {
+    db::DeviceClass *ddc = extractor.default_device_class ();
+    if (ddc) {
+      extractor.register_device_class (ddc);
+    }
+  }
+
+  if (! extractor.device_class ()) {
+    throw tl::Exception (tl::to_string (tr ("No device class registered for device extractor '%s' - cannot extract devices.")), extractor.name ());
+  }
+
+  extractor.extract (dss (), m_layout_index, layers, m_net_clusters, m_device_scaling);
 
   //  transfer errors to log entries
   m_log_entries.insert (m_log_entries.end (), extractor.begin_log_entries (), extractor.end_log_entries ());
diff --git a/src/db/db/dbLayoutToNetlist.h b/src/db/db/dbLayoutToNetlist.h
index 8c0c31d9a..55808bd6b 100644
--- a/src/db/db/dbLayoutToNetlist.h
+++ b/src/db/db/dbLayoutToNetlist.h
@@ -725,6 +725,25 @@ public:
     return m_netlist_extracted;
   }
 
+  /**
+   *  @brief Registers a device class
+   *
+   *  This method registers a device class for device extraction.
+   *  This way of registering device classes is provided alternatively to
+   *  the private device class provided by the device extractors.
+   *  This way, device class management is centralized, which is in
+   *  favor of device-class specific configurations such as SPICE
+   *  profiles.
+   */
+  void register_device_class (const DeviceClass &device_class);
+
+  /**
+   *  @brief Gets a device class by device class name
+   *
+   *  If there is no class with that name, a null pointer is returned.
+   */
+  const DeviceClass *device_class_by_name (const std::string &name) const;
+
   /**
    *  @brief Gets the internal DeepShapeStore object
    *
@@ -1226,6 +1245,7 @@ private:
   db::Connectivity m_conn;
   db::hier_clusters<db::NetShape> m_net_clusters;
   std::unique_ptr<db::Netlist> mp_netlist;
+  tl::shared_collection<db::DeviceClass> m_device_classes;
   std::set<db::DeepLayer> m_dlrefs;
   std::map<std::string, db::DeepLayer> m_named_dls;
   std::map<unsigned int, std::string> m_name_of_layer;
diff --git a/src/db/db/dbNetlistDeviceExtractor.cc b/src/db/db/dbNetlistDeviceExtractor.cc
index 9424007b8..db7f31c73 100644
--- a/src/db/db/dbNetlistDeviceExtractor.cc
+++ b/src/db/db/dbNetlistDeviceExtractor.cc
@@ -78,6 +78,10 @@ void NetlistDeviceExtractor::initialize (db::Netlist *nl)
   m_netlist.reset (nl);
 
   setup ();
+
+  if (! mp_device_class.get () && nl) {
+    mp_device_class.reset (nl->device_class_by_name (m_name));
+  }
 }
 
 static void insert_into_region (const db::NetShape &s, const db::ICplxTrans &tr, db::Region &region)
@@ -88,10 +92,8 @@ static void insert_into_region (const db::NetShape &s, const db::ICplxTrans &tr,
   }
 }
 
-void NetlistDeviceExtractor::extract (db::DeepShapeStore &dss, unsigned int layout_index, const NetlistDeviceExtractor::input_layers &layer_map, db::Netlist &nl, hier_clusters_type &clusters, double device_scaling)
+void NetlistDeviceExtractor::extract (db::DeepShapeStore &dss, unsigned int layout_index, const NetlistDeviceExtractor::input_layers &layer_map, hier_clusters_type &clusters, double device_scaling)
 {
-  initialize (&nl);
-
   std::vector<unsigned int> layers;
   layers.reserve (m_layer_definitions.size ());
 
@@ -153,9 +155,9 @@ void NetlistDeviceExtractor::extract (db::DeepShapeStore &dss, unsigned int layo
   extract_without_initialize (dss.layout (layout_index), dss.initial_cell (layout_index), clusters, layers, device_scaling, dss.breakout_cells (layout_index));
 }
 
-void NetlistDeviceExtractor::extract (db::Layout &layout, db::Cell &cell, const std::vector<unsigned int> &layers, db::Netlist *nl, hier_clusters_type &clusters, double device_scaling, const std::set<db::cell_index_type> *breakout_cells)
+// @@@ needed?
+void NetlistDeviceExtractor::extract (db::Layout &layout, db::Cell &cell, const std::vector<unsigned int> &layers, hier_clusters_type &clusters, double device_scaling, const std::set<db::cell_index_type> *breakout_cells)
 {
-  initialize (nl);
   extract_without_initialize (layout, cell, clusters, layers, device_scaling, breakout_cells);
 }
 
diff --git a/src/db/db/dbNetlistDeviceExtractor.h b/src/db/db/dbNetlistDeviceExtractor.h
index 3da7e5489..f76413619 100644
--- a/src/db/db/dbNetlistDeviceExtractor.h
+++ b/src/db/db/dbNetlistDeviceExtractor.h
@@ -124,6 +124,13 @@ public:
    */
   static const tl::Variant &device_class_property_name ();
 
+  /**
+   *  @brief Initializes the extractor and connects to a netlist
+   *
+   *  This method needs to be called before "extract"
+   */
+  void initialize (Netlist *netlist);
+
   /**
    *  @brief Performs the extraction
    *
@@ -140,7 +147,7 @@ public:
    *
    *  The definition of the input layers is device class specific.
    */
-  void extract (Layout &layout, Cell &cell, const std::vector<unsigned int> &layers, Netlist *netlist, hier_clusters_type &clusters, double device_scaling = 1.0, const std::set<cell_index_type> *breakout_cells = 0);
+  void extract (Layout &layout, Cell &cell, const std::vector<unsigned int> &layers, hier_clusters_type &clusters, double device_scaling = 1.0, const std::set<cell_index_type> *breakout_cells = 0);
 
   /**
    *  @brief Extracts the devices from a list of regions
@@ -149,7 +156,7 @@ public:
    *  named regions for input. These regions need to be of deep region type and
    *  originate from the same layout than the DeepShapeStore.
    */
-  void extract (DeepShapeStore &dss, unsigned int layout_index, const input_layers &layers, Netlist &netlist, hier_clusters_type &clusters, double device_scaling = 1.0);
+  void extract (DeepShapeStore &dss, unsigned int layout_index, const input_layers &layers, hier_clusters_type &clusters, double device_scaling = 1.0);
 
   /**
    *  @brief Clears the log entries
@@ -283,6 +290,23 @@ public:
     return mp_device_class.get ();
   }
 
+  /**
+   *  @brief Gets the default device class
+   *
+   *  The default device class is a fallback device class which is used when
+   *  1.) No device class is registered in the constructor
+   *  2.) No corresponding device class is present in the netlist on extraction
+   *  3.) No corresponding device class is registered in the LayoutToNetlist object
+   *  The object returned is a new object and must be deleted by the caller.
+   *
+   *  This method is mainly used by internal device extractors to link them
+   *  to a default class.
+   */
+  virtual DeviceClass *default_device_class ()
+  {
+    return 0;
+  }
+
   /**
    *  @brief Defines a device terminal in the layout (a region)
    */
@@ -425,13 +449,6 @@ public:
    */
   std::string cell_name () const;
 
-  /**
-   *  @brief Initializes the extractor
-   *  This method will produce the device classes required for the device extraction.
-   *  It is mainly provided for test purposes. Don't call it directly.
-   */
-  void initialize (db::Netlist *nl);
-
 private:
   struct DeviceCellKey
   {
diff --git a/src/db/db/dbNetlistDeviceExtractorClasses.cc b/src/db/db/dbNetlistDeviceExtractorClasses.cc
index c439cc1dd..e1e049180 100644
--- a/src/db/db/dbNetlistDeviceExtractorClasses.cc
+++ b/src/db/db/dbNetlistDeviceExtractorClasses.cc
@@ -31,7 +31,7 @@ namespace db
 //  NetlistDeviceExtractorMOS3Transistor implementation
 
 NetlistDeviceExtractorMOS3Transistor::NetlistDeviceExtractorMOS3Transistor (const std::string &name, bool strict, db::DeviceClassFactory *factory)
-  : db::NetlistDeviceExtractorImplBase (name, factory ? factory : new db::device_class_factory<DeviceClassMOS3Transistor> ()),
+  : db::NetlistDeviceExtractorImplBase (name, factory ? factory : new db::device_class_factory<DeviceClassMOS3Transistor> (strict)),
     m_strict (strict)
 {
   //  .. nothing yet ..
@@ -65,10 +65,6 @@ void NetlistDeviceExtractorMOS3Transistor::setup ()
     define_layer ("tD", 1, "Drain terminal output (default is D)");       // #6
 
   }
-
-  db::DeviceClass *cls = make_class ();
-  cls->set_strict (m_strict);
-  register_device_class (cls);
 }
 
 db::Connectivity NetlistDeviceExtractorMOS3Transistor::get_connectivity (const db::Layout & /*layout*/, const std::vector<unsigned int> &layers) const
@@ -323,7 +319,7 @@ void NetlistDeviceExtractorMOS3Transistor::extract_devices (const std::vector<db
 //  NetlistDeviceExtractorMOS4Transistor implementation
 
 NetlistDeviceExtractorMOS4Transistor::NetlistDeviceExtractorMOS4Transistor (const std::string &name, bool strict, db::DeviceClassFactory *factory)
-  : NetlistDeviceExtractorMOS3Transistor (name, strict, factory ? factory : new db::device_class_factory<db::DeviceClassMOS4Transistor> ())
+  : NetlistDeviceExtractorMOS3Transistor (name, strict, factory ? factory : new db::device_class_factory<db::DeviceClassMOS4Transistor> (strict))
 {
   //  .. nothing yet ..
 }
@@ -366,10 +362,6 @@ void NetlistDeviceExtractorMOS4Transistor::setup ()
     define_layer ("tB", 7, "Well (bulk) terminal output");              // #8 -> W
 
   }
-
-  db::DeviceClass *cls = make_class ();
-  cls->set_strict (is_strict ());
-  register_device_class (cls);
 }
 
 void NetlistDeviceExtractorMOS4Transistor::modify_device (const db::Polygon &rgate, const std::vector<db::Region> & /*layer_geometry*/, db::Device *device)
@@ -395,8 +387,6 @@ void NetlistDeviceExtractorResistor::setup ()
   define_layer ("C", "Contacts");                 // #1
   define_layer ("tA", 1, "A terminal output");    // #2 -> C
   define_layer ("tB", 1, "B terminal output");    // #3 -> C
-
-  register_device_class (make_class ());
 }
 
 db::Connectivity NetlistDeviceExtractorResistor::get_connectivity (const db::Layout & /*layout*/, const std::vector<unsigned int> &layers) const
@@ -508,8 +498,6 @@ void NetlistDeviceExtractorResistorWithBulk::setup ()
   define_layer ("tB", 1, "B terminal output");    // #3 -> C
   define_layer ("W", "Well/Bulk");                // #4
   define_layer ("tW", 4, "W terminal output");    // #5 -> W
-
-  register_device_class (make_class ());
 }
 
 void NetlistDeviceExtractorResistorWithBulk::modify_device (const db::Polygon &res, const std::vector<db::Region> & /*layer_geometry*/, db::Device *device)
@@ -533,8 +521,6 @@ void NetlistDeviceExtractorCapacitor::setup ()
   define_layer ("P2", "Plate 2");                   // #1
   define_layer ("tA", 0, "A terminal output");      // #2 -> P1
   define_layer ("tB", 1, "B terminal output");      // #3 -> P2
-
-  register_device_class (make_class ());
 }
 
 db::Connectivity NetlistDeviceExtractorCapacitor::get_connectivity (const db::Layout & /*layout*/, const std::vector<unsigned int> &layers) const
@@ -610,8 +596,6 @@ void NetlistDeviceExtractorCapacitorWithBulk::setup ()
   define_layer ("tB", 1, "B terminal output");      // #3 -> P2
   define_layer ("W", "Well/Bulk");                  // #4
   define_layer ("tW", 4, "W terminal output");      // #5 -> W
-
-  register_device_class (make_class ());
 }
 
 void NetlistDeviceExtractorCapacitorWithBulk::modify_device (const db::Polygon &cap, const std::vector<db::Region> & /*layer_geometry*/, db::Device *device)
@@ -639,8 +623,6 @@ void NetlistDeviceExtractorBJT3Transistor::setup ()
   define_layer ("tC", 0, "Collector terminal output");                  // #3 -> C
   define_layer ("tB", 1, "Base terminal output");                       // #4 -> B
   define_layer ("tE", 2, "Emitter terminal output");                    // #5 -> E
-
-  register_device_class (make_class ());
 }
 
 db::Connectivity NetlistDeviceExtractorBJT3Transistor::get_connectivity (const db::Layout & /*layout*/, const std::vector<unsigned int> &layers) const
@@ -774,8 +756,6 @@ void NetlistDeviceExtractorBJT4Transistor::setup ()
   define_layer ("S", "Substrate (bulk) terminal output");               // #6
 
   define_layer ("tS", 6, "Substrate (bulk) terminal output");           // #7 -> S
-
-  register_device_class (make_class ());
 }
 
 void NetlistDeviceExtractorBJT4Transistor::modify_device (const db::Polygon &emitter, const std::vector<db::Region> & /*layer_geometry*/, db::Device *device)
@@ -799,8 +779,6 @@ void NetlistDeviceExtractorDiode::setup ()
   define_layer ("N", "N region");                   // #1
   define_layer ("tA", 0, "A terminal output");      // #2 -> P
   define_layer ("tC", 1, "C terminal output");      // #3 -> N
-
-  register_device_class (make_class ());
 }
 
 db::Connectivity NetlistDeviceExtractorDiode::get_connectivity (const db::Layout & /*layout*/, const std::vector<unsigned int> &layers) const
diff --git a/src/db/db/dbNetlistDeviceExtractorClasses.h b/src/db/db/dbNetlistDeviceExtractorClasses.h
index e43221e06..959d7a234 100644
--- a/src/db/db/dbNetlistDeviceExtractorClasses.h
+++ b/src/db/db/dbNetlistDeviceExtractorClasses.h
@@ -49,7 +49,20 @@ class DB_PUBLIC_TEMPLATE device_class_factory
   : public DeviceClassFactory
 {
 public:
-  virtual db::DeviceClass *create_class () const { return new C (); }
+  device_class_factory () : m_strict (-1) { }
+  device_class_factory (bool strict) : m_strict (strict ? 1 : 0) { }
+
+  virtual db::DeviceClass *create_class () const
+  {
+    C *c = new C ();
+    if (m_strict >= 0) {
+      c->set_strict (m_strict != 0);
+    }
+    return c;
+  }
+
+private:
+  int m_strict;
 };
 
 /**
@@ -71,9 +84,9 @@ public:
   }
 
   /**
-   *  @brief Creates the device class object
+   *  @brief Creates the default device class object
    */
-  db::DeviceClass *make_class ()
+  db::DeviceClass *default_device_class ()
   {
     return mp_factory->create_class ();
   }
@@ -108,7 +121,7 @@ public:
   virtual db::Connectivity get_connectivity (const db::Layout &layout, const std::vector<unsigned int> &layers) const;
   virtual void extract_devices (const std::vector<db::Region> &layer_geometry);
 
-  bool is_strict () const
+  virtual bool is_strict () const
   {
     return m_strict;
   }
diff --git a/src/db/db/gsiDeclDbLayoutToNetlist.cc b/src/db/db/gsiDeclDbLayoutToNetlist.cc
index c3368a735..9bde313e0 100644
--- a/src/db/db/gsiDeclDbLayoutToNetlist.cc
+++ b/src/db/db/gsiDeclDbLayoutToNetlist.cc
@@ -657,6 +657,30 @@ Class<db::LayoutToNetlist> decl_dbLayoutToNetlist ("db", "LayoutToNetlist",
     "\n"
     "This method has been introduced in version 0.27.1.\n"
   ) +
+  gsi::method ("register_device_class", &db::LayoutToNetlist::register_device_class, gsi::arg ("device_class"),
+    "@brief Registers a device class for device extraction\n"
+    "\n"
+    "There are two ways of defining the device class for the devices a specific device extractor "
+    "delivers: locally inside the device extractor, and globally inside the \\LayoutToNetlist object. "
+    "The global approach allows to centrally manage device classes outside the device extractors. "
+    "This enables reusing the same device class for SPICE reading and generation and is the key "
+    "for using SPICE profiles in LVS decks for example.\n"
+    "\n"
+    "When you use this method, the given device class is registered and associated with a device "
+    "extractor in \\extract_devices by name. In that case, the device extractor should not register "
+    "a local device class inside a reimplementation of \\GenericDeviceExtractor#setup.\n"
+    "\n"
+    "A corresponding method to query device classes is \\device_class_by_name.\n"
+    "\n"
+    "This method has been introduced in version 0.31.0.\n"
+  ) +
+  gsi::method ("device_class_by_name", &db::LayoutToNetlist::device_class_by_name, gsi::arg ("name"),
+    "@brief Gets a device class by name\n"
+    "\n"
+    "See \\register_device_class for details about this feature.\n"
+    "\n"
+    "This method has been introduced in version 0.31.0.\n"
+  ) +
   gsi::method ("connect", (void (db::LayoutToNetlist::*) (const db::Region &)) &db::LayoutToNetlist::connect, gsi::arg ("l"),
     "@brief Defines an intra-layer connection for the given layer.\n"
     "The layer as a Region object, representing either an original layer created with \\make_layer and its variants or\n"
diff --git a/src/db/db/gsiDeclDbNetlistDeviceExtractor.cc b/src/db/db/gsiDeclDbNetlistDeviceExtractor.cc
index 0f3b6682e..b5c64173b 100644
--- a/src/db/db/gsiDeclDbNetlistDeviceExtractor.cc
+++ b/src/db/db/gsiDeclDbNetlistDeviceExtractor.cc
@@ -321,101 +321,106 @@ Class<GenericDeviceExtractor> decl_GenericDeviceExtractor (decl_dbNetlistDeviceE
     "to the new devices.\n"
   ) +
   gsi::method ("register_device_class", &GenericDeviceExtractor::register_device_class, gsi::arg ("device_class"),
-   "@brief Registers a device class.\n"
-   "The device class object will become owned by the netlist and must not be deleted by\n"
-   "the caller. The name of the device class will be changed to the name given to\n"
-   "the device extractor.\n"
-   "This method shall be used inside the implementation of \\setup to register\n"
-   "the device classes.\n"
+    "@brief Registers a device class.\n"
+    "The device class object will become owned by the netlist and must not be deleted by\n"
+    "the caller. The name of the device class will be changed to the name given to\n"
+    "the device extractor.\n"
+    "This method shall be used inside the implementation of \\setup to register\n"
+    "the device classes.\n"
+    "\n"
+    "Registering a device class in the Extractor is optional. Alternatively, the device class can also "
+    "be registered inside the \\Netter object. In that case the device class corresponding to the "
+    "extractor's name will be used during \\Netter#extract_devices.\n"
   ) +
   gsi::method ("define_layer", (const db::NetlistDeviceExtractorLayerDefinition &(GenericDeviceExtractor::*) (const std::string &name, const std::string &)) &GenericDeviceExtractor::define_layer, gsi::arg ("name"), gsi::arg ("description"),
-   "@brief Defines a layer.\n"
-   "@return The layer descriptor object created for this layer (use 'index' to get the layer's index)\n"
-   "Each call will define one more layer for the device extraction.\n"
-   "This method shall be used inside the implementation of \\setup to define\n"
-   "the device layers. The actual geometries are later available to \\extract_devices\n"
-   "in the order the layers are defined.\n"
+    "@brief Defines a layer.\n"
+    "@return The layer descriptor object created for this layer (use 'index' to get the layer's index)\n"
+    "Each call will define one more layer for the device extraction.\n"
+    "This method shall be used inside the implementation of \\setup to define\n"
+    "the device layers. The actual geometries are later available to \\extract_devices\n"
+    "in the order the layers are defined.\n"
   ) +
   gsi::method ("define_opt_layer", (const db::NetlistDeviceExtractorLayerDefinition &(GenericDeviceExtractor::*) (const std::string &name, size_t fallback, const std::string &)) &GenericDeviceExtractor::define_layer, gsi::arg ("name"), gsi::arg ("fallback"), gsi::arg ("description"),
-   "@brief Defines a layer with a fallback layer.\n"
-   "@return The layer descriptor object created for this layer (use 'index' to get the layer's index)\n"
-   "As \\define_layer, this method allows specification of device extraction layer. In addition to \\define_layout, it features "
-   "a fallback layer. If in the device extraction statement, the primary layer is not given, "
-   "the fallback layer will be used. Hence, this layer is optional. The fallback layer is given by its "
-   "index and must be defined before the layer using the fallback layer is defined. "
-   "For the index, 0 is the first layer defined, 1 the second and so forth."
+    "@brief Defines a layer with a fallback layer.\n"
+    "@return The layer descriptor object created for this layer (use 'index' to get the layer's index)\n"
+    "As \\define_layer, this method allows specification of device extraction layer. In addition to \\define_layer, it features "
+    "a fallback layer. If in the device extraction statement, the primary layer is not given, "
+    "the fallback layer will be used. Hence, this layer is optional. The fallback layer is given by its "
+    "index and must be defined before the layer using the fallback layer is defined. "
+    "For the index, 0 is the first layer defined, 1 the second and so forth."
   ) +
   gsi::method ("create_device", &GenericDeviceExtractor::create_device,
-   "@brief Creates a device.\n"
-   "The device object returned can be configured by the caller, e.g. set parameters.\n"
-   "It will be owned by the netlist and must not be deleted by the caller.\n"
+    "@brief Creates a device.\n"
+    "The device object returned can be configured by the caller, e.g. set parameters.\n"
+    "It will be owned by the netlist and must not be deleted by the caller.\n"
+    "The device created will have the device class specified by \\register_device_class.\n"
   ) +
   gsi::method ("define_terminal", (void (GenericDeviceExtractor::*) (db::Device *, size_t, size_t, const db::Polygon &)) &GenericDeviceExtractor::define_terminal,
     gsi::arg ("device"), gsi::arg ("terminal_id"), gsi::arg ("layer_index"), gsi::arg ("shape"),
-   "@brief Defines a device terminal.\n"
-   "This method will define a terminal to the given device and the given terminal ID. \n"
-   "The terminal will be placed on the layer given by \"layer_index\". The layer index \n"
-   "is the index of the layer during layer definition. The first layer is 0, the second layer 1 etc.\n"
-   "\n"
-   "This version produces a terminal with a shape given by the polygon. Note that the polygon is\n"
-   "specified in database units.\n"
+    "@brief Defines a device terminal.\n"
+    "This method will define a terminal to the given device and the given terminal ID. \n"
+    "The terminal will be placed on the layer given by \"layer_index\". The layer index \n"
+    "is the index of the layer during layer definition. The first layer is 0, the second layer 1 etc.\n"
+    "\n"
+    "This version produces a terminal with a shape given by the polygon. Note that the polygon is\n"
+    "specified in database units.\n"
   ) +
   gsi::method ("define_terminal", (void (GenericDeviceExtractor::*) (db::Device *, size_t, size_t, const db::Box &)) &GenericDeviceExtractor::define_terminal,
     gsi::arg ("device"), gsi::arg ("terminal_id"), gsi::arg ("layer_index"), gsi::arg ("shape"),
-   "@brief Defines a device terminal.\n"
-   "This method will define a terminal to the given device and the given terminal ID. \n"
-   "The terminal will be placed on the layer given by \"layer_index\". The layer index \n"
-   "is the index of the layer during layer definition. The first layer is 0, the second layer 1 etc.\n"
-   "\n"
-   "This version produces a terminal with a shape given by the box. Note that the box is\n"
-   "specified in database units.\n"
+    "@brief Defines a device terminal.\n"
+    "This method will define a terminal to the given device and the given terminal ID. \n"
+    "The terminal will be placed on the layer given by \"layer_index\". The layer index \n"
+    "is the index of the layer during layer definition. The first layer is 0, the second layer 1 etc.\n"
+    "\n"
+    "This version produces a terminal with a shape given by the box. Note that the box is\n"
+    "specified in database units.\n"
   ) +
   gsi::method ("define_terminal", (void (GenericDeviceExtractor::*) (db::Device *, size_t, size_t, const db::Point &)) &GenericDeviceExtractor::define_terminal,
     gsi::arg ("device"), gsi::arg ("terminal_id"), gsi::arg ("layer_index"), gsi::arg ("point"),
-   "@brief Defines a device terminal.\n"
-   "This method will define a terminal to the given device and the given terminal ID. \n"
-   "The terminal will be placed on the layer given by \"layer_index\". The layer index \n"
-   "is the index of the layer during layer definition. The first layer is 0, the second layer 1 etc.\n"
-   "\n"
-   "This version produces a point-like terminal. Note that the point is\n"
-   "specified in database units.\n"
+    "@brief Defines a device terminal.\n"
+    "This method will define a terminal to the given device and the given terminal ID. \n"
+    "The terminal will be placed on the layer given by \"layer_index\". The layer index \n"
+    "is the index of the layer during layer definition. The first layer is 0, the second layer 1 etc.\n"
+    "\n"
+    "This version produces a point-like terminal. Note that the point is\n"
+    "specified in database units.\n"
   ) +
   gsi::method_ext ("define_terminal", &define_terminal_by_names<db::Polygon>,
     gsi::arg ("device"), gsi::arg ("terminal_name"), gsi::arg ("layer_name"), gsi::arg ("shape"),
-   "@brief Defines a device terminal using names for terminal and layer.\n"
-   "\n"
-   "This convenience version of the ID-based \\define_terminal methods allows using names for terminal and layer.\n"
-   "It has been introduced in version 0.28."
+    "@brief Defines a device terminal using names for terminal and layer.\n"
+    "\n"
+    "This convenience version of the ID-based \\define_terminal methods allows using names for terminal and layer.\n"
+    "It has been introduced in version 0.28."
   ) +
   gsi::method_ext ("define_terminal", &define_terminal_by_names<db::Box>,
     gsi::arg ("device"), gsi::arg ("terminal_name"), gsi::arg ("layer_name"), gsi::arg ("shape"),
-   "@brief Defines a device terminal using names for terminal and layer.\n"
-   "\n"
-   "This convenience version of the ID-based \\define_terminal methods allows using names for terminal and layer.\n"
-   "It has been introduced in version 0.28."
+    "@brief Defines a device terminal using names for terminal and layer.\n"
+    "\n"
+    "This convenience version of the ID-based \\define_terminal methods allows using names for terminal and layer.\n"
+    "It has been introduced in version 0.28."
   ) +
   gsi::method_ext ("define_terminal", &define_terminal_by_names<db::Point>,
     gsi::arg ("device"), gsi::arg ("terminal_name"), gsi::arg ("layer_name"), gsi::arg ("point"),
-   "@brief Defines a device terminal using names for terminal and layer.\n"
-   "\n"
-   "This convenience version of the ID-based \\define_terminal methods allows using names for terminal and layer.\n"
-   "It has been introduced in version 0.28."
+    "@brief Defines a device terminal using names for terminal and layer.\n"
+    "\n"
+    "This convenience version of the ID-based \\define_terminal methods allows using names for terminal and layer.\n"
+    "It has been introduced in version 0.28."
   ) +
   gsi::method ("dbu", &GenericDeviceExtractor::dbu,
-   "@brief Gets the database unit\n"
+    "@brief Gets the database unit\n"
   ) +
   gsi::method ("sdbu", &GenericDeviceExtractor::sdbu,
-   "@brief Gets the scaled database unit\n"
-   "Use this unit to compute device properties. It is the database unit multiplied with the\n"
-   "device scaling factor."
+    "@brief Gets the scaled database unit\n"
+    "Use this unit to compute device properties. It is the database unit multiplied with the\n"
+    "device scaling factor."
   ) +
   gsi::method ("error", (void (GenericDeviceExtractor::*) (const std::string &)) &GenericDeviceExtractor::error,
     gsi::arg ("message"),
-   "@brief Issues an error with the given message\n"
+    "@brief Issues an error with the given message\n"
   ) +
   gsi::method ("error", (void (GenericDeviceExtractor::*) (const std::string &, const db::DPolygon &)) &GenericDeviceExtractor::error,
     gsi::arg ("message"), gsi::arg ("geometry"),
-   "@brief Issues an error with the given message and micrometer-units polygon geometry\n"
+    "@brief Issues an error with the given message and micrometer-units polygon geometry\n"
   ) +
   gsi::method_ext ("error", &error1,
     gsi::arg ("message"), gsi::arg ("geometry"),
diff --git a/src/db/unit_tests/dbNetlistDeviceExtractorTests.cc b/src/db/unit_tests/dbNetlistDeviceExtractorTests.cc
index bd5cc8a3f..8074dc0a3 100644
--- a/src/db/unit_tests/dbNetlistDeviceExtractorTests.cc
+++ b/src/db/unit_tests/dbNetlistDeviceExtractorTests.cc
@@ -149,7 +149,8 @@ TEST(3_ClassFactoryTest)
   dl["tS"] = &o1;
   dl["tD"] = &o2;
   dl["tG"] = &o3;
-  ex.extract (dss, 0, dl, nl, cl);
+  ex.initialize (&nl);
+  ex.extract (dss, 0, dl, cl);
 
   //  the generated objects are of MyDeviceClassType
   EXPECT_EQ (dynamic_cast<const MyDeviceClass *> (ex.device_class ()) != 0, true);
@@ -199,7 +200,8 @@ TEST(10_MOS3DeviceExtractorTest)
   dl["tS"] = &o1;
   dl["tD"] = &o2;
   dl["tG"] = &o3;
-  ex.extract (dss, 0, dl, nl, cl);
+  ex.initialize (&nl);
+  ex.extract (dss, 0, dl, cl);
 
   EXPECT_EQ (nl.to_string (),
     "circuit TOP ();\n"
@@ -254,7 +256,8 @@ TEST(11_MOS3DeviceExtractorTestNotRectangularGate)
   dl["tS"] = &o1;
   dl["tD"] = &o2;
   dl["tG"] = &o3;
-  ex.extract (dss, 0, dl, nl, cl);
+  ex.initialize (&nl);
+  ex.extract (dss, 0, dl, cl);
 
   EXPECT_EQ (nl.to_string (),
     "circuit TOP ();\n"
@@ -309,7 +312,8 @@ TEST(12_MOS3DeviceExtractorTestCircular)
   dl["tS"] = &o1;
   dl["tD"] = &o2;
   dl["tG"] = &o3;
-  ex.extract (dss, 0, dl, nl, cl);
+  ex.initialize (&nl);
+  ex.extract (dss, 0, dl, cl);
 
   EXPECT_EQ (nl.to_string (),
     "circuit TOP ();\n"
@@ -368,7 +372,8 @@ TEST(20_MOS4DeviceExtractorTest)
   dl["tD"] = &o2;
   dl["tG"] = &o3;
   dl["tB"] = &o4;
-  ex.extract (dss, 0, dl, nl, cl);
+  ex.initialize (&nl);
+  ex.extract (dss, 0, dl, cl);
 
   EXPECT_EQ (nl.to_string (),
     "circuit TOP ();\n"
@@ -428,7 +433,8 @@ TEST(21_MOS4DeviceExtractorTestNotRectangularGate)
   dl["tD"] = &o2;
   dl["tG"] = &o3;
   dl["tB"] = &o4;
-  ex.extract (dss, 0, dl, nl, cl);
+  ex.initialize (&nl);
+  ex.extract (dss, 0, dl, cl);
 
   EXPECT_EQ (nl.to_string (),
     "circuit TOP ();\n"
@@ -488,7 +494,8 @@ TEST(22_MOS4DeviceExtractorTestCircular)
   dl["tD"] = &o2;
   dl["tG"] = &o3;
   dl["tB"] = &o4;
-  ex.extract (dss, 0, dl, nl, cl);
+  ex.initialize (&nl);
+  ex.extract (dss, 0, dl, cl);
 
   EXPECT_EQ (nl.to_string (),
     "circuit TOP ();\n"
@@ -546,7 +553,8 @@ TEST(30_DMOS3DeviceExtractorTest)
   dl["tS"] = &o1;
   dl["tD"] = &o2;
   dl["tG"] = &o3;
-  ex.extract (dss, 0, dl, nl, cl);
+  ex.initialize (&nl);
+  ex.extract (dss, 0, dl, cl);
 
   EXPECT_EQ (nl.to_string (),
     "circuit TOP ();\n"
@@ -603,7 +611,8 @@ TEST(31_DMOS3DeviceExtractorTestNotRectangularGate)
   dl["tS"] = &o1;
   dl["tD"] = &o2;
   dl["tG"] = &o3;
-  ex.extract (dss, 0, dl, nl, cl);
+  ex.initialize (&nl);
+  ex.extract (dss, 0, dl, cl);
 
   EXPECT_EQ (nl.to_string (),
     "circuit TOP ();\n"
@@ -660,7 +669,8 @@ TEST(32_DMOS3DeviceExtractorTestCircular)
   dl["tS"] = &o1;
   dl["tD"] = &o2;
   dl["tG"] = &o3;
-  ex.extract (dss, 0, dl, nl, cl);
+  ex.initialize (&nl);
+  ex.extract (dss, 0, dl, cl);
 
   EXPECT_EQ (nl.to_string (),
     "circuit TOP ();\n"
@@ -721,7 +731,8 @@ TEST(40_DMOS4DeviceExtractorTest)
   dl["tD"] = &o2;
   dl["tG"] = &o3;
   dl["tB"] = &o4;
-  ex.extract (dss, 0, dl, nl, cl);
+  ex.initialize (&nl);
+  ex.extract (dss, 0, dl, cl);
 
   EXPECT_EQ (nl.to_string (),
     "circuit TOP ();\n"
@@ -783,7 +794,8 @@ TEST(41_DMOS4DeviceExtractorTestNotRectangularGate)
   dl["tD"] = &o2;
   dl["tG"] = &o3;
   dl["tB"] = &o4;
-  ex.extract (dss, 0, dl, nl, cl);
+  ex.initialize (&nl);
+  ex.extract (dss, 0, dl, cl);
 
   EXPECT_EQ (nl.to_string (),
     "circuit TOP ();\n"
@@ -845,7 +857,8 @@ TEST(42_DMOS4DeviceExtractorTestCircular)
   dl["tD"] = &o2;
   dl["tG"] = &o3;
   dl["tB"] = &o4;
-  ex.extract (dss, 0, dl, nl, cl);
+  ex.initialize (&nl);
+  ex.extract (dss, 0, dl, cl);
 
   EXPECT_EQ (nl.to_string (),
     "circuit TOP ();\n"
@@ -903,7 +916,8 @@ TEST(50_BJT3DeviceExtractorTest)
   dl["tE"] = &o1;
   dl["tB"] = &o2;
   dl["tC"] = &o3;
-  ex.extract (dss, 0, dl, nl, cl);
+  ex.initialize (&nl);
+  ex.extract (dss, 0, dl, cl);
 
   EXPECT_EQ (nl.to_string (),
     "circuit TOP ();\n"
@@ -960,7 +974,8 @@ TEST(51_BJT3DeviceExtractorTest)
   dl["tE"] = &o1;
   dl["tB"] = &o2;
   dl["tC"] = &o3;
-  ex.extract (dss, 0, dl, nl, cl);
+  ex.initialize (&nl);
+  ex.extract (dss, 0, dl, cl);
 
   EXPECT_EQ (nl.to_string (),
     "circuit TOP ();\n"
@@ -1017,7 +1032,8 @@ TEST(52_BJT3DeviceExtractorTestLateral)
   dl["tE"] = &o1;
   dl["tB"] = &o2;
   dl["tC"] = &o3;
-  ex.extract (dss, 0, dl, nl, cl);
+  ex.initialize (&nl);
+  ex.extract (dss, 0, dl, cl);
 
   EXPECT_EQ (nl.to_string (),
     "circuit TOP ();\n"
@@ -1074,7 +1090,8 @@ TEST(53_BJT3DeviceExtractorTestMultEmitter)
   dl["tE"] = &o1;
   dl["tB"] = &o2;
   dl["tC"] = &o3;
-  ex.extract (dss, 0, dl, nl, cl);
+  ex.initialize (&nl);
+  ex.extract (dss, 0, dl, cl);
 
   EXPECT_EQ (nl.to_string (),
     "circuit TOP ();\n"
@@ -1136,7 +1153,8 @@ TEST(54_BJT4DeviceExtractorTest)
   dl["tB"] = &o2;
   dl["tC"] = &o3;
   dl["tS"] = &o4;
-  ex.extract (dss, 0, dl, nl, cl);
+  ex.initialize (&nl);
+  ex.extract (dss, 0, dl, cl);
 
   EXPECT_EQ (nl.to_string (),
     "circuit TOP ();\n"
diff --git a/src/db/unit_tests/dbNetlistExtractorTests.cc b/src/db/unit_tests/dbNetlistExtractorTests.cc
index 421decbbb..fbb6751bf 100644
--- a/src/db/unit_tests/dbNetlistExtractorTests.cc
+++ b/src/db/unit_tests/dbNetlistExtractorTests.cc
@@ -259,12 +259,14 @@ TEST(1_DeviceAndNetExtraction)
   dl["SD"] = &rpsd;
   dl["G"] = &rpgate;
   dl["P"] = &rpoly;  //  not needed for extraction but to return terminal shapes
-  pmos_ex.extract (dss, 0, dl, nl, cl);
+  pmos_ex.initialize (&nl);
+  pmos_ex.extract (dss, 0, dl, cl);
 
   dl["SD"] = &rnsd;
   dl["G"] = &rngate;
   dl["P"] = &rpoly;  //  not needed for extraction but to return terminal shapes
-  nmos_ex.extract (dss, 0, dl, nl, cl);
+  nmos_ex.initialize (&nl);
+  nmos_ex.extract (dss, 0, dl, cl);
 
   //  perform the net extraction
 
@@ -495,12 +497,14 @@ TEST(1a_DeviceAndNetExtractionWithTextsAsLabels)
   dl["SD"] = &rpsd;
   dl["G"] = &rpgate;
   dl["P"] = &rpoly;  //  not needed for extraction but to return terminal shapes
-  pmos_ex.extract (dss, 0, dl, nl, cl);
+  pmos_ex.initialize (&nl);
+  pmos_ex.extract (dss, 0, dl, cl);
 
   dl["SD"] = &rnsd;
   dl["G"] = &rngate;
   dl["P"] = &rpoly;  //  not needed for extraction but to return terminal shapes
-  nmos_ex.extract (dss, 0, dl, nl, cl);
+  nmos_ex.initialize (&nl);
+  nmos_ex.extract (dss, 0, dl, cl);
 
   //  perform the net extraction
 
@@ -693,12 +697,14 @@ TEST(2_DeviceAndNetExtractionFlat)
   dl["SD"] = &rpsd;
   dl["G"] = &rpgate;
   dl["P"] = &rpoly;  //  not needed for extraction but to return terminal shapes
-  pmos_ex.extract (dss, 0, dl, nl, cl);
+  pmos_ex.initialize (&nl);
+  pmos_ex.extract (dss, 0, dl, cl);
 
   dl["SD"] = &rnsd;
   dl["G"] = &rngate;
   dl["P"] = &rpoly;  //  not needed for extraction but to return terminal shapes
-  nmos_ex.extract (dss, 0, dl, nl, cl);
+  nmos_ex.initialize (&nl);
+  nmos_ex.extract (dss, 0, dl, cl);
 
   //  perform the net extraction
 
@@ -925,12 +931,14 @@ TEST(3_DeviceAndNetExtractionWithImplicitConnections)
   dl["SD"] = &rpsd;
   dl["G"] = &rpgate;
   dl["P"] = &rpoly;  //  not needed for extraction but to return terminal shapes
-  pmos_ex.extract (dss, 0, dl, nl, cl);
+  pmos_ex.initialize (&nl);
+  pmos_ex.extract (dss, 0, dl, cl);
 
   dl["SD"] = &rnsd;
   dl["G"] = &rngate;
   dl["P"] = &rpoly;  //  not needed for extraction but to return terminal shapes
-  nmos_ex.extract (dss, 0, dl, nl, cl);
+  nmos_ex.initialize (&nl);
+  nmos_ex.extract (dss, 0, dl, cl);
 
   //  perform the net extraction
 
@@ -1196,7 +1204,8 @@ TEST(4_ResAndCapExtraction)
   dl["tG"] = &rpoly;
   dl["tS"] = &rpsd;
   dl["tD"] = &rpsd;
-  pmos_ex.extract (dss, 0, dl, nl, cl);
+  pmos_ex.initialize (&nl);
+  pmos_ex.extract (dss, 0, dl, cl);
 
   dl.clear ();
   dl["SD"] = &rnsd;
@@ -1205,7 +1214,8 @@ TEST(4_ResAndCapExtraction)
   dl["tG"] = &rpoly;
   dl["tS"] = &rnsd;
   dl["tD"] = &rnsd;
-  nmos_ex.extract (dss, 0, dl, nl, cl);
+  nmos_ex.initialize (&nl);
+  nmos_ex.extract (dss, 0, dl, cl);
 
   dl.clear ();
   dl["R"] = &rpoly_res;
@@ -1213,7 +1223,8 @@ TEST(4_ResAndCapExtraction)
   //  terminal patches
   dl["tA"] = &rpoly;
   dl["tB"] = &rpoly;
-  res_ex.extract (dss, 0, dl, nl, cl);
+  res_ex.initialize (&nl);
+  res_ex.extract (dss, 0, dl, cl);
 
   dl.clear ();
   dl["P1"] = &rcap1;
@@ -1221,7 +1232,8 @@ TEST(4_ResAndCapExtraction)
   //  terminal patches
   dl["tA"] = &rmetal1;
   dl["tB"] = &rmetal2;
-  cap_ex.extract (dss, 0, dl, nl, cl);
+  cap_ex.initialize (&nl);
+  cap_ex.extract (dss, 0, dl, cl);
 
 
   //  perform the net extraction
@@ -1446,7 +1458,8 @@ TEST(5_ResAndCapWithBulkExtraction)
   dl["tG"] = &rpoly;
   dl["tS"] = &rpsd;
   dl["tD"] = &rpsd;
-  pmos_ex.extract (dss, 0, dl, nl, cl);
+  pmos_ex.initialize (&nl);
+  pmos_ex.extract (dss, 0, dl, cl);
 
   dl.clear ();
   dl["SD"] = &rnsd;
@@ -1456,7 +1469,8 @@ TEST(5_ResAndCapWithBulkExtraction)
   dl["tG"] = &rpoly;
   dl["tS"] = &rnsd;
   dl["tD"] = &rnsd;
-  nmos_ex.extract (dss, 0, dl, nl, cl);
+  nmos_ex.initialize (&nl);
+  nmos_ex.extract (dss, 0, dl, cl);
 
   dl.clear ();
   dl["R"] = &rpoly_res_sub;
@@ -1465,7 +1479,8 @@ TEST(5_ResAndCapWithBulkExtraction)
   //  terminal patches
   dl["tA"] = &rpoly;
   dl["tB"] = &rpoly;
-  res_substrate_ex.extract (dss, 0, dl, nl, cl);
+  res_substrate_ex.initialize (&nl);
+  res_substrate_ex.extract (dss, 0, dl, cl);
 
   dl.clear ();
   dl["R"] = &rpoly_res_nw;
@@ -1474,7 +1489,8 @@ TEST(5_ResAndCapWithBulkExtraction)
   //  terminal patches
   dl["tA"] = &rpoly;
   dl["tB"] = &rpoly;
-  res_nwell_ex.extract (dss, 0, dl, nl, cl);
+  res_nwell_ex.initialize (&nl);
+  res_nwell_ex.extract (dss, 0, dl, cl);
 
   dl.clear ();
   dl["P1"] = &rcap1_sub;
@@ -1483,7 +1499,8 @@ TEST(5_ResAndCapWithBulkExtraction)
   //  terminal patches
   dl["tA"] = &rmetal1;
   dl["tB"] = &rmetal2;
-  cap_substrate_ex.extract (dss, 0, dl, nl, cl);
+  cap_substrate_ex.initialize (&nl);
+  cap_substrate_ex.extract (dss, 0, dl, cl);
 
   dl.clear ();
   dl["P1"] = &rcap1_nw;
@@ -1492,7 +1509,8 @@ TEST(5_ResAndCapWithBulkExtraction)
   //  terminal patches
   dl["tA"] = &rmetal1;
   dl["tB"] = &rmetal2;
-  cap_nwell_ex.extract (dss, 0, dl, nl, cl);
+  cap_nwell_ex.initialize (&nl);
+  cap_nwell_ex.extract (dss, 0, dl, cl);
 
 
   //  perform the net extraction
@@ -1710,7 +1728,8 @@ TEST(6_BJT3TransistorExtraction)
   dl["tG"] = &rpoly;
   dl["tS"] = &rpsd;
   dl["tD"] = &rpsd;
-  pmos_ex.extract (dss, 0, dl, nl, cl);
+  pmos_ex.initialize (&nl);
+  pmos_ex.extract (dss, 0, dl, cl);
 
   dl.clear ();
   dl["SD"] = &rnsd;
@@ -1720,7 +1739,8 @@ TEST(6_BJT3TransistorExtraction)
   dl["tG"] = &rpoly;
   dl["tS"] = &rnsd;
   dl["tD"] = &rnsd;
-  nmos_ex.extract (dss, 0, dl, nl, cl);
+  nmos_ex.initialize (&nl);
+  nmos_ex.extract (dss, 0, dl, cl);
 
   dl.clear ();
   dl["E"] = &remitter;
@@ -1728,8 +1748,8 @@ TEST(6_BJT3TransistorExtraction)
   dl["C"] = &rbulk;
   //  terminal patches
   dl["tB"] = &rnwell;
-  bjt_ex.extract (dss, 0, dl, nl, cl);
-
+  bjt_ex.initialize (&nl);
+  bjt_ex.extract (dss, 0, dl, cl);
 
   //  perform the net extraction
 
@@ -1911,7 +1931,8 @@ TEST(7_DiodeExtraction)
   dl["N"] = &rn;
   dl["P"] = &rpplus;
   dl["tC"] = &rnwell;
-  diode_ex.extract (dss, 0, dl, nl, cl);
+  diode_ex.initialize (&nl);
+  diode_ex.extract (dss, 0, dl, cl);
 
 
   //  perform the net extraction
@@ -2045,7 +2066,8 @@ TEST(8_DiodeExtractionScaled)
   dl["N"] = &rn;
   dl["P"] = &rpplus;
   dl["tC"] = &rnwell;
-  diode_ex.extract (dss, 0, dl, nl, cl, 2.0);
+  diode_ex.initialize (&nl);
+  diode_ex.extract (dss, 0, dl, cl, 2.0);
 
   //  perform the net extraction
 
@@ -2208,13 +2230,15 @@ TEST(9_StrictDeviceExtraction)
   dl["D"] = &rpd;
   dl["G"] = &rpgate;
   dl["P"] = &rpoly;  //  not needed for extraction but to return terminal shapes
-  pmos_ex.extract (dss, 0, dl, nl, cl);
+  pmos_ex.initialize (&nl);
+  pmos_ex.extract (dss, 0, dl, cl);
 
   dl["S"] = &rns;
   dl["D"] = &rnd;
   dl["G"] = &rngate;
   dl["P"] = &rpoly;  //  not needed for extraction but to return terminal shapes
-  nmos_ex.extract (dss, 0, dl, nl, cl);
+  nmos_ex.initialize (&nl);
+  nmos_ex.extract (dss, 0, dl, cl);
 
   //  perform the net extraction
 
@@ -2443,12 +2467,14 @@ TEST(10_DeviceExtractionWithBreakoutCells)
   dl["SD"] = &rpsd;
   dl["G"] = &rpgate;
   dl["P"] = &rpoly;  //  not needed for extraction but to return terminal shapes
-  pmos_ex.extract (dss, 0, dl, nl, cl);
+  pmos_ex.initialize (&nl);
+  pmos_ex.extract (dss, 0, dl, cl);
 
   dl["SD"] = &rnsd;
   dl["G"] = &rngate;
   dl["P"] = &rpoly;  //  not needed for extraction but to return terminal shapes
-  nmos_ex.extract (dss, 0, dl, nl, cl);
+  nmos_ex.initialize (&nl);
+  nmos_ex.extract (dss, 0, dl, cl);
 
   dss.pop_state ();
 
@@ -2602,12 +2628,14 @@ TEST(11_DeviceExtractionWithSameClass)
   db::NetlistDeviceExtractor::input_layers dl;
   dl["R"] = &rpoly_res;
   dl["C"] = &rpoly_cap;
-  polyres_ex.extract (dss, 0, dl, nl, cl);
+  polyres_ex.initialize (&nl);
+  polyres_ex.extract (dss, 0, dl, cl);
 
   dl.clear ();
   dl["R"] = &rdiff_res;
   dl["C"] = &rdiff_cap;
-  diffres_ex.extract (dss, 0, dl, nl, cl);
+  diffres_ex.initialize (&nl);
+  diffres_ex.extract (dss, 0, dl, cl);
 
   //  perform the net extraction
 
@@ -2725,12 +2753,14 @@ TEST(12_FloatingSubcircuitExtraction)
   dl["SD"] = &rpsd;
   dl["G"] = &rpgate;
   dl["P"] = &rpoly;  //  not needed for extraction but to return terminal shapes
-  pmos_ex.extract (dss, 0, dl, nl, cl);
+  pmos_ex.initialize (&nl);
+  pmos_ex.extract (dss, 0, dl, cl);
 
   dl["SD"] = &rnsd;
   dl["G"] = &rngate;
   dl["P"] = &rpoly;  //  not needed for extraction but to return terminal shapes
-  nmos_ex.extract (dss, 0, dl, nl, cl);
+  nmos_ex.initialize (&nl);
+  nmos_ex.extract (dss, 0, dl, cl);
 
   //  perform the net extraction
 
@@ -2878,12 +2908,14 @@ TEST(13_RemoveDummyPins)
   dl["SD"] = &rpsd;
   dl["G"] = &rpgate;
   dl["P"] = &rpoly;  //  not needed for extraction but to return terminal shapes
-  pmos_ex.extract (dss, 0, dl, nl, cl);
+  pmos_ex.initialize (&nl);
+  pmos_ex.extract (dss, 0, dl, cl);
 
   dl["SD"] = &rnsd;
   dl["G"] = &rngate;
   dl["P"] = &rpoly;  //  not needed for extraction but to return terminal shapes
-  nmos_ex.extract (dss, 0, dl, nl, cl);
+  nmos_ex.initialize (&nl);
+  nmos_ex.extract (dss, 0, dl, cl);
 
   //  perform the net extraction
 
@@ -3027,13 +3059,15 @@ TEST(14_JoinNets)
   dl["G"] = &rpgate;
   dl["W"] = &rnwell;
   dl["P"] = &rpoly;  //  not needed for extraction but to return terminal shapes
-  pmos_ex.extract (dss, 0, dl, nl, cl);
+  pmos_ex.initialize (&nl);
+  pmos_ex.extract (dss, 0, dl, cl);
 
   dl["SD"] = &rnsd;
   dl["G"] = &rngate;
   dl["W"] = &bulk;
   dl["P"] = &rpoly;  //  not needed for extraction but to return terminal shapes
-  nmos_ex.extract (dss, 0, dl, nl, cl);
+  nmos_ex.initialize (&nl);
+  nmos_ex.extract (dss, 0, dl, cl);
 
   //  perform the net extraction
 
@@ -3315,13 +3349,15 @@ TEST(15_SoftConnections)
   dl["G"] = &rpgate;
   dl["W"] = &rnwell;
   dl["P"] = &rpoly;  //  not needed for extraction but to return terminal shapes
-  pmos_ex.extract (dss, 0, dl, nl, cl);
+  pmos_ex.initialize (&nl);
+  pmos_ex.extract (dss, 0, dl, cl);
 
   dl["SD"] = &rnsd;
   dl["G"] = &rngate;
   dl["W"] = &bulk;
   dl["P"] = &rpoly;  //  not needed for extraction but to return terminal shapes
-  nmos_ex.extract (dss, 0, dl, nl, cl);
+  nmos_ex.initialize (&nl);
+  nmos_ex.extract (dss, 0, dl, cl);
 
   //  perform the net extraction
 
@@ -3578,7 +3614,8 @@ TEST(100_issue954)
   dl["G"] = &rpgate;
   dl["W"] = &bulk;
   dl["P"] = &rpoly;  //  not needed for extraction but to return terminal shapes
-  pmos_ex.extract (dss, 0, dl, nl, cl);
+  pmos_ex.initialize (&nl);
+  pmos_ex.extract (dss, 0, dl, cl);
 
   //  perform the net extraction
 
diff --git a/src/drc/drc/built-in-macros/_drc_engine.rb b/src/drc/drc/built-in-macros/_drc_engine.rb
index d8d207390..72b18dcd1 100644
--- a/src/drc/drc/built-in-macros/_drc_engine.rb
+++ b/src/drc/drc/built-in-macros/_drc_engine.rb
@@ -2550,6 +2550,18 @@ CODE
     # The netlist is a RBA::Netlist object. If no netlist is extracted 
     # yet, this method will trigger the extraction process.
     # See \Netter#netlist for a description of this function.
+
+    # %DRC%
+    # @name register_device_class
+    # Registers a device class for extraction and netlist output.
+    # Registering a device class is optional. However, using registered
+    # device classed simplify SPICE netlist writing, as device classes
+    # can be configured with SPICE profiles to customize SPICE output.
+    # In the LVS context, \register_device_class also controls the way
+    # schematic netlists are read from SPICE.
+    # See \Netter#register_device_class for a description of this function.
+    # Also see \Netter#extract_devices for how to use it with registered
+    # device classes.
  
     %w(
       antenna_check
@@ -2567,6 +2579,7 @@ CODE
       top_level
       ignore_extraction_errors
       extract_devices
+      register_device_class
       netlist
       l2n_data
       _l2n_object
diff --git a/src/drc/drc/built-in-macros/_drc_netter.rb b/src/drc/drc/built-in-macros/_drc_netter.rb
index 75506aae2..591090e4e 100644
--- a/src/drc/drc/built-in-macros/_drc_netter.rb
+++ b/src/drc/drc/built-in-macros/_drc_netter.rb
@@ -217,7 +217,6 @@ module DRC
     # @name extract_devices
     # @brief Extracts devices based on the given extractor class, name and device layer selection
     # @synopsis extract_devices(extractor, layer_hash)
-    # @synopsis extract_devices(extractor_class, name, layer_hash)
     # Runs the device extraction for given device extractor class. In the first
     # form, the extractor object is given. In the second form, the extractor's
     # class object and the new extractor's name is given.
@@ -1039,6 +1038,23 @@ module DRC
 
     end
 
+    def _register_device_class(cls)
+      if @devcls_by_name && @devcls_by_name[cls]
+        raise("A device class with name '#{cls.name}' is already registered")
+      end
+      @devcls ||= []
+      @devcls_by_name ||= {}
+      @devcls << cls
+      @devcls_by_name[cls.name] = cls
+    end
+
+    def _devcls_by_name(name)
+      if ! @devcls_by_name || ! @devcls_by_name[name]
+        raise("No device class registered with name #{name}")
+      end
+      @devcls_by_name[name]
+    end
+
   private
 
     def cleanup
diff --git a/src/lvs/lvs/built-in-macros/_lvs_engine.rb b/src/lvs/lvs/built-in-macros/_lvs_engine.rb
index 11959cf40..5c91397ff 100644
--- a/src/lvs/lvs/built-in-macros/_lvs_engine.rb
+++ b/src/lvs/lvs/built-in-macros/_lvs_engine.rb
@@ -231,10 +231,20 @@ module LVS
     # @synopsis flag_missing_ports
     # See \Netter#flag_missing_ports for a description of that function.
 
+    # %LVS%
+    # @name register_device_class
+    # Registers a device class for extraction and netlist input and output.
+    # Registering a device class is optional. However, using registered
+    # device classed simplify SPICE netlist reading and writing, as device classes
+    # can be configured with SPICE profiles to customize SPICE input and output.
+    # See \Netter#register_device_class for a description of this function.
+    # Also see \Netter#extract_devices for how to use it with registered
+    # device classes.
+
     %w(schematic compare split_gates join_symmetric_nets tolerance ignore_parameter enable_parameter disable_parameter 
        blank_circuit align same_nets same_nets! same_circuits same_device_classes equivalent_pins 
        min_caps max_res max_depth max_branch_complexity consider_net_names lvs_data no_lvs_hints
-       flag_missing_ports).each do |f|
+       flag_missing_ports register_device_class).each do |f|
       eval <<"CODE"
         def #{f}(*args)
           _netter.#{f}(*args)
diff --git a/src/lvs/unit_tests/lvsSimpleTests.cc b/src/lvs/unit_tests/lvsSimpleTests.cc
index ae092428e..4255a0084 100644
--- a/src/lvs/unit_tests/lvsSimpleTests.cc
+++ b/src/lvs/unit_tests/lvsSimpleTests.cc
@@ -171,6 +171,13 @@ TEST(13_simple_ringo_device_subcircuits)
   run_test (_this, "ringo_device_subcircuits", "ringo.gds", false, true, std::string (), true);
 }
 
+TEST(13b_simple_ringo_device_subcircuits_devcls)
+{
+  run_test (_this, "ringo_device_subcircuits_devcls", "ringo.gds");
+  //  change case
+  run_test (_this, "ringo_device_subcircuits_devcls", "ringo.gds", false, true, std::string (), true);
+}
+
 TEST(14_simple_ringo_mixed_hierarchy)
 {
   run_test (_this, "ringo_mixed_hierarchy", "ringo_mixed_hierarchy.gds");