diff --git a/__init__.py b/__init__.py
index e78d257..c2a5519 100644
--- a/__init__.py
+++ b/__init__.py
@@ -14,6 +14,7 @@ def register():
         sale.SaleLine,
         sale.CreateSubscriptionStart,
         equipment.OpticalEquipment,
+        equipment.EquipmentMaintenance,
         configuration_equipment.Configuration,
         maintenance.Maintenance,
         maintenance.MaintenanceActivity,
diff --git a/equipment.py b/equipment.py
index d4f595f..0ef06c4 100644
--- a/equipment.py
+++ b/equipment.py
@@ -87,6 +87,9 @@ class OpticalEquipment(Workflow, ModelSQL, ModelView):
                         'equipment','subscription', "Subscriptions",
                         states={'readonly': True}
                                             )
+    maintenance_history = fields.Many2Many('optical_equipment.maintenance-optical_equipment.equipment', 'equipment', 'maintenance', "Maintenances",
+                                           states={'readonly': True}
+                                           )
     software_version = fields.Char("Software version", size=None,
                                    states=_states,)
 
@@ -194,4 +197,21 @@ class OpticalEquipment(Workflow, ModelSQL, ModelView):
     @ModelView.button
     @Workflow.transition('registred')
     def registred(cls, equipments):
-        cls.set_code(equipments)
+        #raise UserError(str(equipments[0].serial))
+        for i in equipments:
+            if i.serial == None:
+                raise UserError(str(i.serial))
+            else:
+                cls.set_code(equipments)
+            
+
+
+class EquipmentMaintenance(ModelSQL):
+    'Optical Equipment - Equipment - Maintenance'
+    __name__='optical_equipment.maintenance-optical_equipment.equipment'
+
+    maintenance = fields.Many2One('optical_equipment.maintenance', 'Maintenances', select=True)
+
+    equipment = fields.Many2One('optical_equipment.equipment', 'Equipment', select=True)
+
+    
diff --git a/purchase.py b/purchase.py
index b28ef17..9719461 100644
--- a/purchase.py
+++ b/purchase.py
@@ -60,7 +60,8 @@ class Purchase(metaclass=PoolMeta):
                             refurbish=line.refurbish,
                             serial=None if line.quantity > 1 else line.serial_equipment,
                             health_register=line.health_register,
-                            software_version=line.software_version)
+                            software_version=line.software_version,
+                            maintenance_frequency="none")
                         equipment.save()
                 else:
                     continue
diff --git a/view/optical_equipment_form.xml b/view/optical_equipment_form.xml
index d61329b..d8fd50d 100644
--- a/view/optical_equipment_form.xml
+++ b/view/optical_equipment_form.xml
@@ -1,55 +1,61 @@
 <?xml version="1.0"?> 
 <!-- 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>
+<form col="6">
     <label name="code"/>
     <field name="code"/>
     <label name="company"/>
     <field name="company"/>
+    <newline/>
     <label name="propietary"/>
     <field name="propietary"/>
     <label name="propietary_address"/>
     <field name="propietary_address"/>
-    <label name="location"/>
-    <field name="location"/>
-    <label name="product"/>
-    <field name="product"/>
-    <label name="equipment_type"/>
-    <field name="equipment_type"/>
-    <label name="use"/>
-    <field name="use"/>
-    <label name="biomedical_class"/>
-    <field name="biomedical_class"/>
-    <label name="calibration"/>
-    <field name="calibration"/>
-    <newline/>
-    <label name="mark_category"/>
-    <field name="mark_category"/>
-    <label name="model_category"/>
-    <field name="model_category"/>
-    <label name="reference_category"/>
-    <field name="reference_category"/>
-    <label name="refurbish"/>
-    <field name="refurbish"/>
-    <label name="software_version"/>
-    <field name="software_version"/>
-    <label name="useful_life"/>
-    <field name="useful_life"/>
-    <label name="warranty"/>
-    <field name="warranty"/>
-    <newline/>
-    <label name="maintenance_frequency"/>
-    <field name="maintenance_frequency"/>
-    <label name="serial"/>
-    <field name="serial"/>
-    <label name="health_register"/>
-    <field name="health_register"/>
-    <label name="origin_country"/>
-    <field name="origin_country"/>
-    <notebook>
+    <notebook colspan="6">
+	<page string="General" id="general_equipment">
+	    <label name="location"/>
+	    <field name="location"/>
+	    <label name="product"/>
+	    <field name="product"/>
+	    <label name="equipment_type"/>
+	    <field name="equipment_type"/>
+	    <label name="use"/>
+	    <field name="use"/>
+	    <label name="biomedical_class"/>
+	    <field name="biomedical_class"/>
+	    <label name="calibration"/>
+	    <field name="calibration"/>
+	    <newline/>
+	    <label name="mark_category"/>
+	    <field name="mark_category"/>
+	    <label name="model_category"/>
+	    <field name="model_category"/>
+	    <label name="reference_category"/>
+	    <field name="reference_category"/>
+	    <label name="refurbish"/>
+	    <field name="refurbish"/>
+	    <label name="software_version"/>
+	    <field name="software_version"/>
+	    <label name="useful_life"/>
+	    <field name="useful_life"/>
+	    <label name="warranty"/>
+	    <field name="warranty"/>
+	    <newline/>
+	    <label name="maintenance_frequency"/>
+	    <field name="maintenance_frequency"/>
+	    <label name="serial"/>
+	    <field name="serial"/>
+	    <label name="health_register"/>
+	    <field name="health_register"/>
+	    <label name="origin_country"/>
+	    <field name="origin_country"/>
+	</page>
 	<page string="Subscriptions" id="subscriptions_equipment">
 	    <field name="subscription_history"/>
 	</page>
+	<page string="Maintenances" id="maintenances_equipment">
+	    <field name="maintenance_history"/>
+	</page>
     </notebook>
     <group col="2" colspan="2" id="button">
 	<button name="draft"/>
diff --git a/view/optical_equipment_serial_tree.xml b/view/optical_equipment_serial_tree.xml
index 07c28a1..89f1442 100644
--- a/view/optical_equipment_serial_tree.xml
+++ b/view/optical_equipment_serial_tree.xml
@@ -11,4 +11,6 @@
     <field name="product"/>
     <field name="equipment_type"/>
     <field name="serial" expand="1"/>
+    <button name="registred"/>
 </tree>
+