diff --git a/equipment.py b/equipment.py
index 695e7dc..65e0526 100644
--- a/equipment.py
+++ b/equipment.py
@@ -1,12 +1,19 @@
 from collections import defaultdict
 from trytond.pool import Pool
 from trytond.model import ModelSQL, ModelView, Unique, fields
+from trytond.pyson import Eval
 from trytond.exceptions import UserError
 
 class OpticalEquipment(ModelSQL, ModelView):
     'Optical Equipment'
     __name__ = 'optical_equipment.equipment'
 
+    code_readinly = fields.Function(
+        fields.Boolean("Code Readonly"), 'get_code_readonly')
+    code = fields.Char(
+        "Code", select=True,states={
+            'readonly': Eval('code_readonly', False),
+            })
     company = fields.Many2One('company.company', "Company")
     location = fields.Many2One('stock.location', "Location")
     propietary = fields.Many2One('party.party', "Propietary")
@@ -19,8 +26,13 @@ class OpticalEquipment(ModelSQL, ModelView):
     biomedical_class = fields.Char('Biomedical Class')
     main_tecnology = fields.Char('Main tecnology')
     calibration = fields.Boolean("Apply calibration", readonly=True)
-    mark_category = fields.Many2One('product.category', 'Mark', required=True)
-    model_category  = fields.Many2One('product.category', "Model", required=True)
+    mark_category = fields.Many2One('product.category', 'Mark', required=True,
+                                    domain=[('parent', '=', None),
+                                            ('accounting', '=', False)],
+                                    )
+    model_category  = fields.Many2One('product.category', "Model", required=True,
+                                      domain=[('parent', '=', Eval('mark_category')),
+                                              ('accounting', '=', False)],)
     reference = fields.Char("Reference", size=None)
     origin_country = fields.Many2One('country.country',"Origin Country")
     software_version = fields.Char("Software version", size=None)
@@ -47,3 +59,22 @@ class OpticalEquipment(ModelSQL, ModelView):
             ('serial_unique', Unique(t, t.serial),
              'optical_equipment.msg_serial_unique')
             ]
+
+    def default_code_readonly(cls):
+        pool = Pool()
+        Configuration = pool.get('optical_equipment.configuration')
+        config = Configuration(1)
+        return bool(config.equipment_sequence)
+
+    def get_code_readonly(self, name):
+        return self.default_code_readonly()
+
+    @classmethod
+    def _new_code(cls):
+        pool = Pool()
+        Configuration = pool.get('optical_equipment.configuration')
+        config = Configuration(1)
+        sequence = config.equipment_sequence
+        if sequence:
+            return sequence.get()
+
diff --git a/view/optical_equipment_form.xml b/view/optical_equipment_form.xml
index 9c14628..23fe8c5 100644
--- a/view/optical_equipment_form.xml
+++ b/view/optical_equipment_form.xml
@@ -2,6 +2,8 @@
 <!-- This file is part of Tryton.  The COPYRIGHT file at the top level of
      this repository contains the full copyright notices and license terms. -->
 <form>
+    <label name="code"/>
+    <field name="code"/>
     <label name="company"/>
     <field name="company"/>
     <label name="location"/>
diff --git a/view/optical_equipment_tree.xml b/view/optical_equipment_tree.xml
index 46928a0..8fb6c0e 100644
--- a/view/optical_equipment_tree.xml
+++ b/view/optical_equipment_tree.xml
@@ -2,6 +2,7 @@
 <!-- This file is part of Tryton.  The COPYRIGHT file at the top level of
      this repository contains the full copyright notices and license terms. -->
 <tree>
+    <field name="code"/>
     <field name="company"/>
     <field name="location"/>
     <field name="propietary"/>